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Spastic Paraplegia 4 (SPG4) is a debilitating neurodegenerative disorder characterized by progressive muscle weakness and spasticity in the lower limbs, often leading to gait impairment. Central to SPG4 pathology is the die‐back degeneration of corticospinal tracts, primarily driven by mutations in the spastin protein encoded by the SPAST gene. SPAST gives rise to two major spastin isoforms, M1‐ and M87‐spastin, which are generated from distinct translation initiation sites. Although spastin is implicated in various cellular functions, the specific roles of each isoform in the pathogenesis of SPG4 remain poorly understood. This review offers an overview of the genetic and structural organization of the M1‐ and M87‐spastin isoforms, highlighting their distinct and overlapping functions, and exploring their potential roles in the haploinsufficiency and gain‐of‐toxicity mechanisms underlying SPG4. We also present a novel perspective on the evolutionary emergence of M1‐spastin and its potential unique involvement in the pathogenesis of SPG4. Drawing upon the latest research, we propose an intriguing hypothesis regarding the hetero‐oligomerization of M1‐ and M87‐spastin, exploring how their interaction may drive disease progression and open new avenues for therapeutic intervention. By integrating the current research with these fresh insights, we seek to illuminate the complex molecular mechanisms driving SPG4 and foster the development of innovative therapeutic strategies. This review not only incorporates existing knowledge but also lays the groundwork for future studies aimed at uncovering the isoform‐specific roles of spastin in SPG4, with the ultimate goal of advancing targeted treatments for this challenging neurodegenerative disorder. © 2024 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

FARS2‐associated hereditary spastic paraplegia, later onset spastic paraplegia type 77, is a rarely neurodegenerative disease. Here, we reported two affected siblings in an autosomal recessive spastic paraplegia family with a pseudo‐homozygous missense variant and Alu‐mediated exon 5 deletion in FARS2. Both patients gradually developed altered gaits and weakness in both lower limbs. In our literature review, spastic paraplegia type 77 shows high heterogeneity in clinical manifestations. Our study broadens the scope of pathogenic mechanisms of SPG77 resulting from compound heterozygous mutations in FARS2 and provides strong evidence that deletion in FARS2 due to recombination event mediated by Alu element. [ABSTRACT FROM AUTHOR]

Background Objectives Methods Results Conclusions Hereditary spastic paraplegia (HSP) is characterized by progressive lower limb weakness and spasticity, with unknown genetic cause in many cases.To identify novel genetic causes of HSP.Phenotypic characterization, genetic screening, transcriptome sequencing, and peroneal nerve biopsy were conducted in a Chinese HSP family.We found a homoplasmic MT‐TV (mitochondrial tRNAVal) mutation, m.1661A > G, present in all affected individuals across four generations of a family with complex HSP. Fourth‐generation affected individuals displayed earlier onset, likely due to presumptive anticipation, and greater symptom severity, potentially caused by decreased mitochondrial DNA (mtDNA) copy number. Upregulation of mitochondrial autophagy genes in these patients suggested that MT‐TV mutations could lead to reduced mtDNA copy number. Neural biopsies revealed ultrastructural abnormalities in myelin and mitochondria.The rare MT‐TV m.1661A > G mutation is associated with HSP. Variations in mtDNA copy number may play a causal role in differences among clinical phenotypes. © 2024 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Senescence, marked by permanent cell cycle arrest may contribute to the decline in regenerative potential and neuronal function, thereby promoting neurodegenerative disorders. In this study, we employed whole exome sequencing to identify a previously unreported biallelic missense variant in SVBP (p.Leu49Pro) in six patients from three unrelated families. These affected individuals present with a complex hereditary spastic paraplegia (HSP), peripheral neuropathy, verbal apraxia, and intellectual disability, exhibiting a milder phenotype compared to patients with nonsense SVBP mutations described previously. Consistent with SVBP's primary role as a chaperone necessary for VASH‐mediated tubulin detyrosination, both patient fibroblasts with the p.Leu49Pro mutation, and HeLa cells harboring an SVBP knockdown exhibit microtubule dynamic instability and alterations in pericentriolar material (PCM) component trafficking and centrosome cohesion. In patient fibroblasts, structural abnormalities in the centrosome trigger mitotic errors and cellular senescence. Notably, premature senescence characterized by elevated levels of p16INK4, was also observed in patient peripheral blood mononuclear cells (PBMCs). Taken together, our findings underscore the critical role of SVBP in the development and maintenance of the central nervous system, providing novel insights associating cytokinesis failure with cortical motor neuron disease and intellectual disability. [ABSTRACT FROM AUTHOR]

Hereditary spastic paraplegia (HSP) with thin corpus callosum can be due to a variety of genetic causes, the most common of which are biallelic variants in SPG11 (HSP11). Only six cases of neuropathologic examination of HSP11 have been reported. Here we present neuropathological findings in another case of HSP11 with novel mutation (homozygous c.6439_6442del) and clinical features of three additional cases of HSP11. These four cases of HSP11 had similar disease courses with prominent lower extremity weakness and spasticity but varied cognitive symptoms and brain magnetic resonance imaging (MRI) findings. Neuropathological examination of one case included ex vivo MRI of the cerebrum, histologic and immunohistochemical evaluation, and Western blot for SPG11. The case was notable for a small cerebrum with decreased volume of cortex, white matter, and deep gray nuclei. The corpus callosum was thin, and the substantia nigra showed marked pallor. Microscopically, the cortex had normal lamination and mild loss of neurons with mild gliosis, the corpus callosum was thin with limited gliosis, and the substantia nigra had marked decrease in neurons and pigment, with minimal gliosis. In contrast, the basal ganglia, thalamus, and spinal cord (anterior horns, corticospinal, and spinocerebellar tracts) had prominent neuron loss and gliosis. Myelin‐laden macrophages were found in multiple sites but were most common in the corpus callosum. No hyperphosphorylated tau or TDP‐43 aggregates, Lewy bodies, or amyloid β plaques were found. Compared to control, SPG11 was absent in HSP11 brain and markers of autophagy were elevated by Western blot. Comparison with prior reports of HSP with thin corpus callosum and HSP11 demonstrates a disease with a broad range of structural changes of the brain, including features of abnormal development and degeneration. [ABSTRACT FROM AUTHOR]

Background and purpose: Hereditary spastic paraplegias (HSPs) comprise a group of inherited neurodegenerative disorders characterized by progressive spasticity and weakness. Botulinum toxin has been approved for lower limb spasticity following stroke and cerebral palsy, but its effects in HSPs remain underexplored. We aimed to characterize the effects of botulinum toxin on clinical, gait, and patient‐reported outcomes in HSP patients and explore the potential of mobile digital gait analysis to monitor treatment effects and predict treatment response. Methods: We conducted a prospective, observational, multicenter study involving ambulatory HSP patients treated with botulinum toxin tailored to individual goals. Comparing data at baseline, after 1 month, and after 3 months, treatment response was assessed using clinical parameters, goal attainment scaling, and mobile digital gait analysis. Machine learning algorithms were used for predicting individual goal attainment based on baseline parameters. Results: A total of 56 patients were enrolled. Despite the heterogeneity of treatment goals and targeted muscles, botulinum toxin led to a significant improvement in specific clinical parameters and an improvement in specific gait characteristics, peaking at the 1‐month and declining by the 3‐month follow‐up. Significant correlations were identified between gait parameters and clinical scores. With a mean balanced accuracy of 66%, machine learning algorithms identified important denominators to predict treatment response. Conclusions: Our study provides evidence supporting the beneficial effects of botulinum toxin in HSP when applied according to individual treatment goals. The use of mobile digital gait analysis and machine learning represents a novel approach for monitoring treatment effects and predicting treatment response. [ABSTRACT FROM AUTHOR]

Background and purpose: White matter (WM) damage is the main target of hereditary spastic paraplegia (HSP), but mounting evidence indicates that genotype‐specific grey matter (GM) damage is not uncommon. Our aim was to identify and compare brain GM and WM damage patterns in HSP subtypes and investigate how gene expression contributes to these patterns, and explore the relationship between GM and WM damage. Methods: In this prospective single‐centre cohort study from 2019 to 2022, HSP patients and controls underwent magnetic resonance imaging evaluations. The alterations of GM and WM patterns were compared between groups by applying a source‐based morphometry approach. Spearman rank correlation was used to explore the associations between gene expression and GM atrophy patterns in HSP subtypes. Mediation analysis was conducted to investigate the interplay between GM and WM damage. Results: Twenty‐one spastic paraplegia type 4 (SPG4) patients (mean age 50.7 years ± 12.0 SD, 15 men), 21 spastic paraplegia type 5 (SPG5) patients (mean age 29.1 years ± 12.8 SD, 14 men) and 42 controls (sex‐ and age‐matched) were evaluated. Compared to controls, SPG4 and SPG5 showed similar WM damage but different GM atrophy patterns. GM atrophy patterns in SPG4 and SPG5 were correlated with corresponding gene expression (ρ = 0.30, p = 0.008, ρ = 0.40, p < 0.001, respectively). Mediation analysis indicated that GM atrophy patterns were mediated by WM damage in HSP. Conclusions: Grey matter atrophy patterns were distinct between SPG4 and SPG5 and were not only secondary to WM damage but also associated with disease‐related gene expression. Clinical trial registration no. NCT04006418. [ABSTRACT FROM AUTHOR]

Summary: We report a case of monozygotic twin sisters with hereditary spastic paraplegia type 4 (SPG4) and epilepsy, only one of whom had a diagnosis of narcolepsy type 1 (NT1). The older sister with NT1 exhibited excessive daytime sleepiness, cataplexy, sleep‐onset rapid eye movement period in the multiple sleep latency test, and decreased orexin levels in cerebrospinal fluid. Both sisters had HLA‐DRB1*15:01‐DQB1*06:02 and were further identified to have a novel missense mutation (c.1156A > C, p.Asn386His) in the coding exon of the spastin (SPAST) gene. The novel missense mutation might be involved in the development of epilepsy. This case is characterised by a combined diagnosis of SPG4 and epilepsy, and it is the first report of NT1 combined with epilepsy and genetically confirmed SPG4. The fact that only one of the twins has NT1 suggests that acquired and environmental factors are important in the pathogenesis of NT1. [ABSTRACT FROM AUTHOR]

Spastic paraplegia type 4 (SPG4), caused by SPAST mutations, is the most predominant subtype of hereditary spastic paraplegia. Most documented SPG4 patients present as pure form, with the complex form rarely reported. We described the clinical and genetic features of 20 patients with complex phenotypes of SPG4 and further explored the genotype–phenotype correlations. We collected detailed clinical data of all SPG4 patients and assessed their phenotypes. SPAST gene mutations were identified by Multiplex ligation‐dependent probe amplification in combination with whole exome sequencing. We further performed statistical analysis in genotype and phenotype among patients with various manifestations and different variants. Out of 90 SPG4 patients, 20 patients (male:female = 16:4) with additional neurologic deficits, namely complex form, were included in our study. The bimodal distribution of age of onset at 0–10 and 21–40 years old is concluded. On cranial MRI, obvious white matter lesions can be observed in five patients. We identified 9 novel and 8 reported SPAST mutations, of which 11 mutations were located in AAA (ATPase associated with various cellular activities) domain. The AAA cassette of spastin is the hottest mutated region among complex SPG4. All patients with cognitive impairment (CI) are males (n = 9/9). Additionally, 80% patients with ataxia are due to frameshift mutations (n = 4/5). Overall, our study summarized and analyzed the genetic and phenotypic characteristics of complex SPG4, making up over 1/5 of in‐house SPG4 cohort, among which CI and ataxia are the most common features. Further studies are expected to explore the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Background: Autosomal recessive spastic ataxia ofCharlevoix–Saguenay (ARSACS) is a rare neurodegenerative disorder characterizedby early‐onset cerebellar ataxia, peripheral sensorimotor neuropathy, and lowerlimb spasticity. We present clinical andgenetic data of the first Bulgarian patients diagnosed with ARSACS by wholeexome sequencing (WES). Methods: Variant filtering was performed usinglocally established pipeline and the selected variants were analysed by Sangersequencing. All patients underwent clinical examination and testingincluding the standard rating scales for spastic paraplegia and ataxia. Results: Five different SACS gene variants, three of which novel, have been identified inpatients from three different ethnic groups. In addition to the classicalclinical triad, brain MRI revealed cerebellar atrophy, linear pontineT2‐hypointensities, and hyperintense rim lateral tothalamus combined with retinal nerve fiber layer thickening on opticcoherence tomography (OCT). Conclusion: We expand the mutation, geographic, and phenotypic spectrum of ARSACS, adding Bulgaria to the world map of the disease, and drawing attention to the fact that it is still misdiagnosed. We demonstrated that brain MRI and OCT are necessary clinical tests for ARSACS diagnosis, even if one of the cardinal clinical features is lacking [ABSTRACT FROM AUTHOR]

Objective: TFG mutations have previously been implicated in autosomal recessive hereditary spastic paraplegia (HSP), also known as SPG57. This study aimed to investigate the clinical and molecular features of TFG mutations in a Taiwanese HSP cohort. Methods: Genetic analysis of TFG was conducted in 242 unrelated Taiwanese HSP patients using a targeted resequencing panel covering the entire coding regions of TFG. Functional assays were performed using an in vitro cell model to assess the impact of TFG variants on protein function. Additionally, other representative TFG mutant proteins were examined to understand the broader implications of TFG mutations in HSP. Results: The study identified a novel homozygous TFG c.177A>C (p.(Lys59Asn)) variant in a family with adolescent‐onset, pure form HSP. Functional analysis revealed that the Lys59Asn TFG variant, similar to other HSP‐associated TFG mutants, exhibited a low affinity between TFG monomers and abnormal assembly of TFG homo‐oligomers. These structural alterations led to aberrant intracellular distribution, compromising TFG's protein secretion function and resulting in decreased cellular viability. Interpretation: These findings confirm that the homozygous TFG c.177A>C (p.(Lys59Asn)) variant is a novel cause of SPG57. The study expands our understanding of the clinical and mutational spectrum of TFG‐associated diseases, highlighting the functional defects associated with this specific TFG variant. Overall, this research contributes to the broader comprehension of the genetic and molecular mechanisms underlying HSP. [ABSTRACT FROM AUTHOR]

Objective: Krabbe disease (KD) is a multisystem neurodegenerative disorder with severe disability and premature death, mostly with an infancy/childhood onset. In rare cases of late‐onset phenotypes, symptoms are often milder and difficult to diagnose. We here present a translational approach combining diagnostic and biochemical analyses of a male patient with a progressive gait disorder starting at the age of 44 years, with a final diagnosis of late‐onset KD (LOKD). Methods: Additionally to cerebral MRI, protein structural analyses of the β‐galactocerebrosidase protein (GALC) were performed. Moreover, expression, lysosomal localization, and activities of β‐glucocerebrosidase (GCase), cathepsin B (CTSB), and cathepsin D (CTSD) were analyzed in leukocytes, fibroblasts, and lysosomes of fibroblasts. Results: Exome sequencing revealed biallelic likely pathogenic variants: GALC exons 11–17: 33 kb deletion; exon 4: missense variant (c.334A>G, p.Thr112Ala). We detected a reduced GALC activity in leukocytes and fibroblasts. While histological KD phenotypes were absent in fibroblasts, they showed a significantly decreased activities of GCase, CTSB, and CTSD in lysosomal fractions, while expression levels were unaffected. Interpretation: The presented LOKD case underlines the age‐dependent appearance of a mildly pathogenic GALC variant and its interplay with other lysosomal proteins. As GALC malfunction results in reduced ceramide levels, we assume this to be causative for the here described decrease in CTSB and CTSD activity, potentially leading to diminished GCase activity. Hence, we emphasize the importance of a functional interplay between the lysosomal enzymes GALC, CTSB, CTSD, and GCase, as well as between their substrates, and propose their conjoined contribution in KD pathology. [ABSTRACT FROM AUTHOR]

The article discusses a case study of a 17-year-old boy with COQ4-associated hereditary spastic paraplegia, a rare mitochondrial disease. The patient presented with gait instability, falls, and cognitive impairment, with neuroimaging showing a unique "ears of the lynx" sign. Genetic testing revealed COQ4 mutations, and CoQ10 supplementation led to partial improvement in symptoms. The study highlights the importance of further research on the efficacy of CoQ10 supplementation in patients with COQ4 mutation-associated HSP. [Extracted from the article]

The article discusses a case study of a 4-year-old boy with psychomotor delay, microcephaly, and other physical symptoms, but without cerebellar atrophy or other central nervous system abnormalities. The boy was found to have a compound heterozygous genotype of novel variants in the WDR73 gene, which is associated with a form of autosomal recessive Galloway-Mowat syndrome. This case sheds light on the role of WDR73 mutations in neurodevelopmental disabilities and provides insights into the pathogenic mechanisms of this gene. [Extracted from the article]

This article discusses a case of delayed diagnosis of cervical myelopathy in an adult with Weaver syndrome. Weaver syndrome is a rare genetic condition characterized by bony overgrowth and intellectual impairment. The patient in this case had progressive lower limb spasticity and a history of corrective surgeries for clubfoot and hip dysplasia. Despite a hospital admission and medical workup, the cause of her loss of ambulatory ability was not identified until she was seen by a physiatrist who ordered electrodiagnostic testing and an MRI. The MRI revealed spinal cord compression and myelomalacia, leading to surgery and stabilization of her symptoms. The article highlights the importance of maintaining a high level of suspicion for cervical myelopathy in patients with Weaver syndrome and the need to address cognitive biases that may affect diagnostic and therapeutic decision-making. [Extracted from the article]

Background: Spastic paraplegia 11 (SPG11) is the most prevalent form of autosomal recessive hereditary spastic paraplegia, resulting from biallelic pathogenic variants in the SPG11 gene (MIM *610844). Methods: The proband is a 36‐year‐old female referred for genetic evaluation due to cognitive dysfunction, gait impairment, and corpus callosum atrophy (brain MRI was normal at 25‐years‐old). Diagnostic approaches included CGH array, next‐generation sequencing, and whole transcriptome sequencing. Results: CGH array revealed a 180 kb deletion located upstream of SPG11. Sequencing of SPG11 uncovered two rare single nucleotide variants: the novel variant c.3143C>T in exon 17 (in cis with the deletion), and the previously reported pathogenic variant c.6409C>T in exon 34 (in trans). Whole transcriptome sequencing revealed that the variant c.3143C>T caused exon 17 skipping. Conclusion: We report a novel sequence variant in the SPG11 gene resulting in exon 17 skipping, which, along with a nonsense variant, causes Spastic Paraplegia 11 in our proband. In addition, a deletion upstream of SPG11 was identified in the patient, whose implication in the phenotype remains uncertain. Nonetheless, the deletion apparently affects cis‐regulatory elements of the gene, suggesting a potential new pathogenic mechanism underlying the disease in a subset of undiagnosed patients. Our findings further support the hypothesis that the origin of thin corpus callosum in patients with SPG11 is of progressive nature. [ABSTRACT FROM AUTHOR]

Objective: To further comprehend the phenotype of multiple mitochondrial dysfunction syndrome type 3 (MMDS3:OMIM#615330) caused by IBA57 mutation. We present a case involving a patient who experienced acute neurological regression, and the literature was reviewed. Methods: Clinical data and laboratory test results were collected; early language and development progress were tested; and genetic testing was performed. Bioinformatics analysis was performed using Mutation Taster and PolyPhen‐2, and the literature in databases such as PubMed and CNKI was searched using MMDS3 and IBA57 as keywords. Results: The child, aged 1 year and 2 months, had motor decline, unable to sit alone, limited right arm movement, hypotonia, hyperreflexia of both knees, and Babinski sign positivity on the right side, accompanied by nystagmus. Blood lactate levels were elevated at 2.50 mmol/L. Brain MR indicated slight swelling in the bilateral frontoparietal and occipital white matter areas and the corpus callosum, with extensive abnormal signals on T1 and T2 images, along with the semioval center and occipital lobes bilaterally. The multiple abnormal signals in the brain suggested metabolic leukoencephalopathy. Whole‐exome sequencing analysis revealed that the child had two heterozygous mutations in the IBA57 gene, c.286T>C (p.Y96H) (likely pathogenic, LP) and c.992T>A (p.L331Q) (variant of uncertain significance, VUS). As of March 2023, a literature search showed that 56 cases of MMDS3 caused by IBA57 mutation had been reported worldwide, with 35 cases reported in China. Among the 35 IBA57 mutations listed in the HGMD database, there were 28 missense or nonsense mutations, 2 splicing mutations, 2 small deletions, and 3 small insertions. Conclusion: MMDS3 predominantly manifests in infancy, with primary symptoms including feeding difficulties, neurological functional regression, muscle weakness, with severe cases potentially leading to mortality. Diagnosis is supported by elevated lactate levels, multisystem impairment (including auditory and visual systems), and distinctive MRI findings. Whole‐exome sequencing is crucial for diagnosis. Currently, cocktail therapy offers symptomatic relief. [ABSTRACT FROM AUTHOR]

Biallelic mutations in the coenzyme Q7 (COQ7) encoding gene were recently identified as a genetic cause of distal hereditary motor neuropathy. Here, we explored the clinical, electrophysiological, pathological, and genetic characteristics of a Chinese patient with spastic paraplegia associated with recessive variants in COQ7. This patient carried a novel c.322C>A (p.Pro108Thr) homozygous variant. Sural biopsy revealed mild mixed axonal and demyelinating degeneration. Immunoblotting showed a significant decrease in the COQ7 protein level in the patient's fibroblasts. This study confirmed that COQ7 variant as a genetic cause of HSP, and further extended spastic paraplegia to the phenotypic spectrum of COQ7‐related disorders. [ABSTRACT FROM AUTHOR]

Introduction: Hereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders characterized by progressive degeneration of upper motor neurons. Homozygous or compound heterozygous variants in COQ4 have been reported to cause primary CoQ10 deficiency‐7 (COQ10D7), which is a mitochondrial disease. Aims: We aimed to screened COQ4 variants in a cohort of HSP patients. Methods: A total of 87 genetically unidentified HSP index patients and their available family members were recruited. Whole exome sequencing (WES) was performed in all probands. Functional studies were performed to identify the pathogenicity of those uncertain significance variants. Results: In this study, five different COQ4 variants were identified in three Chinese HSP pedigrees and two variants were novel, c.87dupT (p.Arg30*), c.304C>T (p.Arg102Cys). More importantly, we firstly described two early‐onset pure HSP caused by COQ4 variants. Functional studies in patient‐derived fibroblast lines revealed a reduction cellular CoQ10 levels and the abnormal mitochondrial structure. Conclusions: Our findings revealed that bilateral variants in the COQ4 gene caused HSP predominant phenotype, expanding the phenotypic spectrum of the COQ4‐related disorders. [ABSTRACT FROM AUTHOR]

This article discusses a case study of a pediatric patient with spastic paraplegia, a neurodegenerative disorder characterized by weakness and spasticity in the lower extremities. The patient had no family history of the condition and was initially diagnosed with cerebral palsy. However, further genetic analysis revealed a novel disease-causing variant in the ATL1 gene, which is associated with hereditary spastic paraplegia. This finding highlights the importance of accurate molecular diagnosis for prognosis estimation, patient management, and genetic counseling. [Extracted from the article]

This article discusses a case study of a 16.5-year-old girl with a progressive disorder caused by biallelic variants in the HPDL gene. The girl initially presented with mild lower limb hypertonia and poor social interaction, but later developed an ataxic-spastic syndrome and regression of developmental milestones. She also experienced an episode of acute ophthalmoplegia with a Wernicke-like MRI pattern. Treatment with oral steroids and antioxidant vitamins resulted in the resolution of her symptoms. The article highlights the need for broad genetic testing, such as exome sequencing, in the diagnosis of HPDL-related disorders. [Extracted from the article]

Objective: X‐linked adrenoleukodystrophy is caused by mutations in the peroxisomal half‐transporter ABCD1. The most common manifestation is adrenomyeloneuropathy, a hereditary spastic paraplegia of adulthood. The present study set out to understand the role of neuronal ABCD1 in mice and humans with adrenomyeloneuropathy. Methods: Neuronal expression of ABCD1 during development was assessed in mice and humans. ABCD1‐deficient mice and human brain tissues were examined for corresponding pathology. Next, we silenced ABCD1 in cholinergic Sh‐sy5y neurons to investigate its impact on neuronal function. Finally, we tested adeno‐associated virus vector‐mediated ABCD1 delivery to the brain in mice with adrenomyeloneuropathy. Results: ABCD1 is highly expressed in neurons located in the periaqueductal gray matter, basal forebrain and hypothalamus. In ABCD1‐deficient mice (Abcd1−/y), these structures showed mild accumulations of α‐synuclein. Similarly, healthy human controls had high expression of ABCD1 in deep gray nuclei, whereas X‐ALD patients showed increased levels of phosphorylated tau, gliosis, and complement activation in those same regions, albeit not to the degree seen in neurodegenerative tauopathies. Silencing ABCD1 in Sh‐sy5y neurons impaired expression of functional proteins and decreased acetylcholine levels, similar to observations in plasma of Abcd1−/y mice. Notably, hind limb clasping in Abcd1−/y mice was corrected through transduction of ABCD1 in basal forebrain neurons following intracerebroventricular gene delivery. Interpretation: Our study suggests that the basal forebrain–cortical cholinergic pathway may contribute to dysfunction in adrenomyeloneuropathy. Rescuing peroxisomal transport activity in basal forebrain neurons and supporting glial cells might represent a viable therapeutic strategy. ANN NEUROL 2024;95:442–458 [ABSTRACT FROM AUTHOR]

Movement disorders manifest in various hereditary neurodegenerative diseases. We reported a young man who presented with progressive upper limb dystonia, spastic tetraplegia, and ataxia. Whole‐exome sequencing (WES) revealed a novel variant, c.2357A > G, in the dynamin domain of OPA1. No mtDNA deletion was detected in muscle by long‐range PCR. Atrophy and decreased glucose metabolism of the basal ganglia were discovered. Decreased mtDNA copy number, fragmented mitochondria, slightly impaired oxidative phosphorylation, and increased autophagy were detected in mutant fibroblasts. Evident oxidative phosphorylation impairment and mtDNA deletions were not involved in the pathogenicity of this mutation unlike mutations in the GTPase domain of OPA1. [ABSTRACT FROM AUTHOR]

Microcephaly is a rare neurodevelopmental disorder characterized by reduced skull circumference and brain volume that occurs sporadically in farm animals. We investigated an early‐onset neurodegenerative disorder observed in seven lambs of purebred Kerry Hill sheep. Clinical signs included inability to stand or severe ataxia, convulsions, and early death. Diagnostic imaging and brain necropsy confirmed microcephaly. The pedigree of the lambs suggested monogenic autosomal recessive inheritance. We sequenced the genome of one affected lamb, and comparison with 115 control genomes revealed a single private protein‐changing variant. This frameshift variant, MFSD2A: c.285dupA, p.(Asp96fs*9), represents a 1‐bp duplication predicted to truncate 80% of the open reading frame. MFSD2A is a transmembrane protein that is essential for maintaining blood–brain barrier homeostasis and plays a key role in regulating brain lipogenesis. Human MFSD2A pathogenic variants are associated with a neurodevelopmental disorder with progressive microcephaly, spasticity, and brain imaging abnormalities (NEDMISBA, OMIM 616486). Here we present evidence for the occurrence of a recessively inherited form of microcephaly in sheep due to a loss‐of‐function variant in MFSD2A (OMIA 002371‐9940). To the best of our knowledge, this is the first report of a spontaneous MFSD2A variant in domestic animals. [ABSTRACT FROM AUTHOR]

Children with cerebral palsy (CP) exhibit impaired motor control and significant muscle weakness due to a brain lesion. However, studies that assess the relationship between brain activity and performance on dynamic functional muscle strength assessments in CP are needed. The aim of this study was to determine the effect of a progressive lateral step‐up test on prefrontal cortex (PFC) hemodynamic activity in children with CP. Fourteen ambulatory children with spastic CP (Gross Motor Function Classification System level I; 5–11 y) and 14 age‐ and sex‐matched typically developing control children completed a progressive lateral step‐up test at incremental step heights (0, 10, 15 and 20 cm) using their non‐dominant lower limb. Hemodynamic activity in the PFC was assessed using non‐invasive, portable functional neuroimaging (functional near‐infrared spectroscopy). Children with CP completed fewer repetitions at each step height and exhibited lower PFC hemodynamic activity across step heights compared to controls. Lower PFC activation in CP was maintained after statistically controlling for the number of repetitions completed at each step height. PFC hemodynamic activity was not associated with LSUT task performance in children with CP, but a positive relationship was observed in controls at the most challenging 20 cm step height. The results suggest there is an altered PFC recruitment pattern in children with CP during a highly dynamic test of functional strength. Further studies are needed to explore the mechanisms underlying the suppressed PFC activation observed in children with CP compared to typically developing children. [ABSTRACT FROM AUTHOR]

Muscle ultrasonography is frequently used to improve the understanding of musculoskeletal impairments in children with spastic cerebral palsy (SCP). So far, most studies on muscle morphology and architecture have included typically developing children and children with SCP with similar ancestry, being mainly Caucasian. Less is known about differences in muscle morphology between children with different ancestral backgrounds. Therefore, the aim of this study was to compare muscle morphology and architecture of the medial gastrocnemius in typically developing children with African, South Asian and Southeast Asian descent from Suriname. This explorative cohort study identified children as Maroon (Ghana, African descent), Hindustani (India, South Asian) or Javanese (Indonesia, Southeast Asian), aged 5–10 years. Using 3D freehand ultrasound with the subject prone, the following medial gastrocnemius parameters were defined: muscle tendon unit (MTU) length, muscle belly length, tendon length, muscle volume, muscle thickness, anatomical cross‐sectional area (ACSA), fascicle length, pennation angle, and physiological cross‐sectional area (PCSA). In addition, differences between ancestral groups were assessed for the length of the MTU, muscle, tendon and fascicles in two passive stretch conditions corresponding to an externally applied joint torque of 1Nm and 4Nm. One‐way ANOVA with post hoc t‐tests were used to investigate differences between the ancestral groups. In total, 100 Hindustani (n = 34), Javanese (n = 34) and Maroon (n = 32) children were included. For statistical analyses, we matched the children by age, which resulted in groups of 25 children per ancestral group (n = 75). There were no differences found in MTU length, muscle belly length, ACSA, PCSA and muscle volume. Tendon length, fascicle length and pennation angle were different between ancestral groups. Compared to Javanese children, tendon length was longer (p = 0.001) and pennation angle (p = 0.001) was larger in Maroon children and fascicle length was shorter in both Maroon and Hindustani children (p < 0.001). While there was a difference found in MTU length at different conditions of passive stretch between ancestries, no differences were found in the muscle, tendon and fascicles. This is the first study that investigated macroscopic morphological and architectural parameters for the medial gastrocnemius in one extended cohort of typically developing children, stratified in three ancestral subgroups. The current results imply that ancestry‐specific reference data for children are needed, especially for tendon length, fascicle length and pennation angle when investigating altered muscle morphology in neurological or neuromuscular pathologies, such as SCP. Future studies should report the ancestral background when describing muscle morphology and architecture of children and ancestral specifications should be included in normative databases. The current study investigated the differences in the morphology and architecture of the medial gastrocnemius in children 5–10 years old from three ancestral groups, namely Maroon (Ghana, West African), Hindustani (India, South Asian) and Javanese (Indonesia, Southeast Asian). There were no differences in muscle‐tendon unit length, muscle belly length, anatomical cross‐sectional area, physiological cross‐sectional area and muscle volume, while tendon length, fascicle length and pennation angle were different between ancestral groups. Current results imply that ancestry‐specific reference data for children are needed, especially for tendon length, fascicle length and pennation angle when investigating altered muscle morphology and architecture in neurological or neuromuscular pathologies, such as spastic Cerebral Palsy. [ABSTRACT FROM AUTHOR]

This article reports on two sisters with recessive dystrophic epidermolysis bullosa (RDEB) caused by novel variants in the COL7A1 gene. The sisters experienced symptoms such as intense cutaneous pruritus, skin blistering, erosion, and ulceration on their hands and feet, as well as nail dystrophy. Whole-exome sequencing revealed two heterozygous variants in COL7A1, which were inherited from their parents and segregated with the phenotype in the family. These variants were classified as uncertain significance but were believed to affect the fibronectin III-like domains in the NC-1 domain of the protein, resulting in a milder phenotype. This study contributes to the understanding of genotype-phenotype correlation in RDEB. [Extracted from the article]

This article discusses a unique case of spastic paraplegia 7 (SPG7), a hereditary condition characterized by progressive lower extremity weakness and spasticity. The patient in this case presented with ataxia, periodic alternating nystagmus (PAN), and progressive lower extremity spasticity. The diagnosis was confirmed through the identification of compound heterozygous mutations in the SPG7 gene. This case highlights the clinical variability and genetic complexity of SPG7 and emphasizes the importance of multidisciplinary care in diagnosis and treatment. [Extracted from the article]

Genetic variants in SPAST are the most common cause of hereditary spastic paraplegia (HSP), entitled spastic paraplegia type 4 (SPG4). Inheritance is autosomal dominant, and age of onset can vary from childhood to adulthood. Pathogenic SPAST variants are often observed in isolated cases, likely due to reduced penetrance and clinical variability. We report an isolated case of SPG4 associated with a novel likely pathogenic variant in SPAST. A 38-year-old woman presented with an eight-year history of progressive difficulty walking. Neurological examination revealed spastic paraparesis in the absence of upper motor neuron dysfunction, sensory deficits, or intellectual disability. Magnetic resonance imaging (MRI) of the brain and spinal cord was normal. No family members had similar complaints. Genetic analysis revealed a novel heterozygous sequence variant in SPAST, c.1751A > G p.(Asp584Gly) (NM_014946.4). The affected amino acid is highly conserved among orthologue and paralogue species. Four other nucleotide substitutions predicted to affect the same amino acid, a "hot spot", have been reported previously in adult-onset HSP. This report describes a novel SPAST variant in a female with HSP without a known family history of the disorder. [ABSTRACT FROM AUTHOR]

Background: Very long‐chain fatty acids (VLCFAs) composed of more than 20 carbon atoms are essential in the biosynthesis of cell membranes in the brain, skin, and retina. VLCFAs are elongated beyond 28 carbon atoms by ELOVL4 enzyme. Variants in ELOVL4 are associated with three Mendelian disorders: autosomal dominant (AD) Stargardt‐like macular dystrophy type 3, AD spinocerebellar ataxia, and autosomal recessive disorder congenital ichthyosis, spastic quadriplegia and impaired intellectual development (ISQMR). Only seven subjects from five unrelated families with ISQMR have been described, all of which have biallelic single‐nucleotide variants. Methods: We performed clinical exome sequencing on probands from four unrelated families with neuro‐ichthyosis. Results: We identified three novel homozygous ELOVL4 variants. Two of the families originated from the same Saudi tribe and had the exact homozygous exonic deletion in ELOVL4, while the third and fourth probands had two different novel homozygous missense variants. Seven out of the eight affected subjects had profound developmental delay, epilepsy, axial hypotonia, peripheral hypertonia, and ichthyosis. Delayed myelination and corpus callosum hypoplasia were seen in two of five subjects with brain magnetic rosonance imaging and cerebral atrophy in three. Conclusion: Our study expands the allelic spectrum of ELOVL4‐related ISQMR. The detection of the same exonic deletion in two unrelated Saudi family from same tribe suggests a tribal founder mutation. [ABSTRACT FROM AUTHOR]

Biallelic mutations in AP4S1, the σ4 subunit of the adaptor protein complex 4 (AP‐4), lead to autosomal recessive spastic paraplegia 52 (SPG52). It is a subtype of AP‐4‐associated hereditary spastic paraplegia (AP‐4‐HSP), a complex childhood‐onset neurogenetic disease characterized by progressive spastic paraplegia of the lower limbs. This disease has so far lacked effective treatment, in part due to a lack of suitable animal models. Here, we used CRISPR/Cas9 technology to generate a truncation mutation in the ap4s1 gene in zebrafish. The ap4s1 truncation led to motor impairment, delayed neurodevelopment, and distal axonal degeneration. This animal model is useful for further research into AP‐4 and AP‐4‐HSP. [ABSTRACT FROM AUTHOR]

Limb girdle muscular dystrophies (LGMD) are a genetically heterogeneous group of muscular dystrophies. The study presents an overview of molecular characteristics of a large cohort of LGMD patients who are representative of the Czech LGMD population. We present 226 LGMD probands in which 433 mutant alleles carrying 157 different variants with a supposed pathogenic effect were identified. Fifty‐four variants have been described only in the Czech LGMD population so far. LGMD R1 caplain3‐related is the most frequent subtype of LGMD involving 53.1% of patients with genetically confirmed LGMD, followed by LGMD R9 FKRP‐related (11.1%), and LGMD R12 anoctamin5‐related (7.1%). If we consider identified variants, then all but five were small‐scale variants. One large gene deletion was identified in the LAMA2 gene and two deletions in each of CAPN3 and SGCG. We performed comparison our result with other published studies. The results obtained in the Czech LGMD population clearly differ from the outcome of other LGMD populations in two aspects—we have a more significant proportion of patients with LGMD R1 calpain3‐related and a smaller proportion of LGMD R2 dysferlin‐related. [ABSTRACT FROM AUTHOR]

Chemodenervation with botulinum neurotoxin type A (BoNTA) is the preferred method for focal spasticity management among various treatment options. While BoNTA injection is considered safe, its widespread use and increasing evidence raise safety concerns. In this paper, we present a patient with central pontine myelinolysis, a rare disease, who developed acute respiratory distress syndrome on the third day after BoNTA application to the spastic gastrocnemius muscle group and required intubation in the intensive care unit due to this complication. To our knowledge, this is the first case reported in the literature to develop an acute pulmonary complication after BoNTA injection into spastic lower extremity muscles. [ABSTRACT FROM AUTHOR]

Background: Isolated congenital bilateral absence of vas deferens (iCBAVD) in men results in obstructive azoospermia and is mainly caused by pathogenic variants in cystic fibrosis transmembrane conductance regulator (CFTR) or adhesion G protein‐coupled receptor G2 (ADGRG2). Methods: The next‐generation sequencing (NGS) was used to screen the mutations in the proband, and Sanger sequencings were performed to validate the compound heterozygous variant of CFTR in his family members. Protein structure simulation was performed to discover the potential pathological mechanism. Results: This study reported novel compound heterozygous CFTR mutations (NM:000492.4, Intron: 5T; c.3965_3969dupTTGGG: p.R1325Gfs*5) in two brothers with obstructive azoospermia. The compound heterozygous CFTR mutations were first screened out by NGS in an infertile male patient who exhibited iCBAVD from a nonconsanguineous Chinese family. Histological analysis of the testicular biopsy from this patient revealed normal spermatogenesis and mature spermatozoa were observed in the seminiferous tubules. Surprisingly, the same compound heterozygous CFTR mutations were also observed in his brothers who also exhibited iCBAVD, with their parents being a heterozygous carrier for the mutations, as verified by Sanger sequencing. Protein structure simulation revealed that these mutations potentially led to impaired ATP‐binding ability of CFTR. Conclusion: We identified novel compound heterozygous CFTR mutations in two brothers and summarized the literature regarding CFTR mutation and male infertility. Our study may contribute to the genetic diagnosis of iCBAVD and future genetic counseling. [ABSTRACT FROM AUTHOR]

Objective: Hereditary spastic paraplegia (HSP) has been reported rarely because of a monoallelic variant in ERLIN2. The present study aimed at describing a novel autosomal dominant ERLIN2 pedigree in a Chinese family and exploring the possible mechanism of HSP caused by ERLIN2 variants. Methods: The proband and his family underwent a comprehensive medical history inquiry and neurological examinations. Whole‐exome sequencing was performed on the proband, and Sanger sequencing was performed on some family members. HeLa cell lines and mouse primary cortical neurons were used for immunofluorescence (IF) and reverse transcription‐PCR (RT‐PCR). Results: Seven patients were clinically diagnosed with pure spastic paraplegia in four consecutive generations with the autosomal dominant inheritance model. All patients presented juvenile‐adolescent onset and gradually worsening pure HSP phenotype. Whole‐exome sequencing of the proband and Sanger sequencing of all available family members identified a novel heterozygous c.212 T>C (p.V71A) variant in exon 8 of the ERLIN2 gene. The c.212 T>C demonstrated a high pathogenic effect score through functional prediction. RT‐PCR and IF analysis of overexpressed V71A revealed an altered ER morphology and increased XBP‐1S mRNA levels, suggesting the activation of ER stress. Overexpression of V71A in primary cultured cortical neurons promoted axon growth. Interpretation: The novel c.212 T>C heterozygous variant in human ERLIN2 caused pure HSP. Moreover, c.212 T>C heterozygous variant in ERLIN2 increased ER stress and affected axonal development. [ABSTRACT FROM AUTHOR]

Bladder cancer (BCa) is one of the most common malignancies worldwide. Although multiple efforts have been made, the 5‐year survival rate of patients with BCa remains unchanged in recent years. Overexpression of the epidermal growth factor receptor (EGFR) is found in ≈74% of BCa tissue specimens; however, current EGFR‐based targeted therapies show little benefit for BCa patients, as the EGFR downstream pathways appear to be circumvented by other receptor tyrosine kinases (RTKs). In this study, two natural products are identified, namely triptolide (TPL) and hesperidin (HSP), that target and inhibit the EGFR and its downstream PI3K/AKT pathway in BCa. To synergistically combine triptolide and hesperidin, a succinic acid linker was employed to conjugate them and formed an amphiphilic TPL‐HSP EGFR‐targeting prodrug (THE), which further self‐assembled to generate nanoparticles (THE NPs). These NPs allowed the EGFR‐targeted delivery of the triptolide and hesperidin, and simultaneous inhibition of the EGFR and PI3K/AKT both in vitro and in vivo. This study provides a promising EGFR‐targeted delivery approach with the dual inhibition of the EGFR and PI3K/AKT, while also exhibiting a high drug loading and low toxicity. Our formulation may be a suitable option to deliver natural products for BCa treatment by EGFR‐targeted therapy. [ABSTRACT FROM AUTHOR]

Aim: Hereditary neuropathy with liability to pressure palsies (HNPP) is a peripheral neuropathy with autosomal dominant inheritance. Diagnosis can be made from the characteristic abnormalities determined by nerve conduction studies (NCS), including subclinical deficits at physiological compression sites. Heterozygous deletion of the chromosome 17p11.2–p12 region including the peripheral myelin protein 22 gene (PMP22) is the cause in the majority of cases. However, the loss of function of PMP22 due to frameshift‐causing insertion/deletion, missense, nonsense, or splice‐site disrupting variants cause HNPP in some patients. We report a case of a patient diagnosed with HNPP on the basis of clinical features and the results of NCS. No deletions of PMP22 were detected by fluorescence in situ hybridization. Methods: We performed direct nucleotide sequence analysis and identified a heterozygous variant, c.78 + 3G > T, in PMP22. Since this variant is located outside the canonical splice site at the exon 2–intron 2 junction, we investigated whether the variant causes aberrant splicing and leads to the skipping of exon 2 of PMP22 by in vitro minigene splicing assay. Results: We demonstrated that the c.78 + 3G > T variant causes the skipping of exon 2 and leads to loss of function of the mutant allele. Conclusion: Searching for sequence variants located outside the canonical splice sites should also be considered even when deletion of PMP22 is not found in a patient with a clinical diagnosis suggesting HNPP. [ABSTRACT FROM AUTHOR]

Objectives: Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disease caused by over 70 genes, with a significant number of patients still genetically unsolved. In this study, we recruited a suspected HSP family characterized by spasticity, developmental delay, ataxia and hypomyelination, and intended to reveal its molecular etiology by whole exome sequencing (WES) and long‐read sequencing (LRS) analyses. Methods: WES was performed on 13 individuals of the family to identify the causative mutations, including analyses of SNVs (single‐nucleotide variants) and CNVs (copy number variants). Accurate circular consensus (CCS) long‐read sequencing (LRS) was used to verify the findings of CNV analysis from WES. Results: SNVs analysis identified a missense variant c.195G>T (p.E65D) of MORF4L2 at Xq22.2 co‐segregating in this family from WES data. Further CNVs analysis revealed a microdeletion, which was adjacent to the MORF4L2 gene, also co‐segregating in this family. LRS verified this microdeletion and confirmed the deletion range (chrX: 103,690,507–103,715,018, hg38) with high resolution at nucleotide level accuracy. Interpretations: In this study, we identified an Xq22.2 microdeletion (about 24.5 kb), which contains distal enhancers of the PLP1 gene, as a likely cause of SPG2 in this family. The lack of distal enhancers may result in transcriptional repression of PLP1 in oligodendrocytes, potentially affecting its role in the maintenance of myelin, and causing SPG2 phenotype. This study has highlighted the importance of noncoding genomic alterations in the genetic etiology of SPG2. [ABSTRACT FROM AUTHOR]

Objective: Hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative disorders characterized by slowly progressive lower limb spasticity and weakness. HSP type 54 (SPG54) is autosomal recessively inherited and caused by mutations in the DDHD2 gene. This study investigated the clinical characteristics and molecular features of DDHD2 mutations in a cohort of Taiwanese patients with HSP. Methods: Mutational analysis of DDHD2 was performed for 242 unrelated Taiwanese patients with HSP. The clinical, neuroimaging, and genetic features of the patients with biallelic DDHD2 mutations were characterized. A cell‐based study was performed to assess the effects of the DDHD2 mutations on protein expression. Results: SPG54 was diagnosed in three patients. Among them, two patients carried compound heterozygous DDHD2 mutations, p.[R112Q];[Y606*] and p.[R112Q];[p.D660H], and the other one was homozygous for the DDHD2 p.R112Q mutation. DDHD2 p.Y606* is a novel mutation, whereas DDHD2 p.D660H and p.R112Q have been reported in the literature. All three patients manifested adult onset complex HSP with additional cerebellar ataxia, polyneuropathy, or cognitive impairment. Brain proton magnetic resonance spectroscopy revealed an abnormal lipid peak in thalamus of all three patients. In vitro studies demonstrated that all the three DDHD2 mutations were associated with a considerably lower DDHD2 protein level. Interpretation: SPG54 was detected in approximately 1.2% (3 of 242) of the Taiwanese HSP cohort. This study expands the known mutational spectrum of DDHD2, provides molecular evidence of the pathogenicity of the DDHD2 mutations, and underlines the importance of considering SPG54 as a potential diagnosis of adult‐onset HSP. [ABSTRACT FROM AUTHOR]

Cerebellar ataxia is often the first and irreversible outcome in the disease of ataxia‐telangiectasia (A‐T), as a consequence of selective cerebellar Purkinje neuronal degeneration. A‐T is an autosomal recessive disorder resulting from the loss‐of‐function mutations of the ataxia‐telangiectasia–mutated ATM gene. Over years of research, it now becomes clear that functional ATM—a serine/threonine kinase protein product of the ATM gene—plays critical roles in regulating both cellular DNA damage response and central carbon metabolic network in multiple subcellular locations. The key question arises is how cerebellar Purkinje neurons become selectively vulnerable when all other cell types in the brain are suffering from the very same defects in ATM function. This review intended to comprehensively elaborate the unexpected linkages between these two seemingly independent cellular functions and the regulatory roles of ATM involved, their integrated impacts on both physical and functional properties, hence the introduction of selective vulnerability to Purkinje neurons in the disease will be addressed. [ABSTRACT FROM AUTHOR]

Biallelic pathogenic variants in RNASEH2C cause Aicardi‐Goutières syndrome 3 (AGS3, MIM #610329), a rare early‐onset encephalopathy characterized by intermittent unexplained fever, chilblains, irritability, progressive microcephaly, dystonia, spasticity, severe psychomotor retardation and abnormal brain imaging. Currently, approximately 50 individuals with AGS3 and 19 variants in RNASEH2C have been revealed. Here, we reported the novel clinical manifestations and genotypic information of three unrelated Chinese patients with AGS3 caused by pathogenic variants in RNASEH2C. In addition to three novel missense variants (c.101G>A, p.Cys34Tyr; c.401T>A, p.Leu134Gln and c.434G>T, p.Arg145Leu), one missense variant (c.194G>A, p.Gly65Asp) reoccurred in all patients but was completely absent in South Asian and other ethnicities. Our study expanded the variant spectrum of RNASEH2C and identified RNASEH2C c.194G>A as a Chinese‐specific founder mutation. The novel phenotypes, including mouth ulcers, hip dysplasia, retarded dentition and hypogonadism, observed in our patients greatly enriched the clinical characteristics of AGS3. [ABSTRACT FROM AUTHOR]

Background: Oral clefts and ectrodactyly are common, heterogeneous birth defects. We performed whole‐exome sequencing (WES) analysis in a Syrian family. The proband presented with both orofacial clefting and ectrodactyly but not ectodermal dysplasia as typically seen in ectrodactyly, ectodermal dysplasia, and cleft lip/palate syndrome‐3. A paternal uncle with only an oral cleft was deceased and unavailable for analysis. Methods: Variant annotation, Mendelian inconsistencies, and novel variants in known cleft genes were examined. Candidate variants were validated using Sanger sequencing, and pathogenicity assessed by knocking out the tp63 gene in zebrafish to evaluate its role during zebrafish development. Results: Twenty‐eight candidate de novo events were identified, one of which is in a known oral cleft and ectrodactyly gene, TP63 (c.956G > T, p.Arg319Leu), and confirmed by Sanger sequencing. Conclusion: TP63 mutations are associated with multiple autosomal dominant orofacial clefting and limb malformation disorders. The p.Arg319Leu mutation seen in this patient is de novo but also novel. Two known mutations in the same codon (c.956G > A, p.(Arg319His; rs121908839, c.955C > T), p.Arg319Cys) cause ectrodactyly, providing evidence that mutating this codon is deleterious. While this TP63 mutation is the best candidate for the patient's clinical presentation, whether it is responsible for the entire phenotype is unclear. Generation and characterization of tp63 knockout zebrafish showed necrosis and rupture of the head at 3 days post‐fertilization (dpf). The embryonic phenotype could not be rescued by injection of zebrafish or human messenger RNA (mRNA). Further functional analysis is needed to determine what proportion of the phenotype is due to this mutation. [ABSTRACT FROM AUTHOR]

Background and objectives: Hereditary spastic paraplegias (HSPs) are heterogenous genetic disorders. While peripheral nerve involvement is frequent in spastic paraplegia 7 (SPG7), the evidence of peripheral nerve involvement in SPG4 is more controversial. We aimed to characterize lower extremity peripheral nerve involvement in SPG4 and SPG7 by quantitative magnetic resonance neurography (MRN). Methods: Twenty‐six HSP patients carrying either the SPG4 or SPG7 mutation and 26 age‐/sex‐matched healthy controls prospectively underwent high‐resolution MRN with large coverage of the sciatic and tibial nerve. Dual‐echo turbo‐spin‐echo sequences with spectral fat‐saturation were utilized for T2‐relaxometry and morphometric quantification, while two gradient‐echo sequences with and without an off‐resonance saturation rapid frequency pulse were applied for magnetization transfer contrast (MTC) imaging. HSP patients additionally underwent detailed neurologic and electroneurographic assessments. Results: All microstructural (proton spin density [ρ], T2‐relaxation time, magnetization transfer ratio) and morphometric (cross‐sectional area) quantitative MRN markers were decreased in SPG4 and SPG7 indicating chronic axonopathy. ρ was superior in differentiating subgroups and identifying subclinical nerve damage in SPG4 and SPG7 without neurophysiologic signs of polyneuropathy. MRN markers correlated well with clinical scores and electroneurographic results. Conclusions: MRN characterizes peripheral nerve involvement in SPG4 and SPG7 as a neuropathy with predominant axonal loss. Evidence of peripheral nerve involvement in SPG4 and SPG7, even without electroneurographically manifest polyneuropathy, and the good correlation of MRN markers with clinical measures of disease progression, challenge the traditional view of the existence of HSPs with isolated pyramidal signs and suggest MRN markers as potential progression biomarkers in HSP. [ABSTRACT FROM AUTHOR]

Background: and Purpose: Hereditary spastic paraplegias (HSP) are a group of clinically diverse genetic disorders that share the neurologic symptom of difficulty in walking due to progressive serious muscle weakness and spasticity in the legs. This study describes a physiotherapy program for improving the functional ability of a child diagnosed with complicated HSP and reports the treatment results. Methods: A 10‐year‐old boy with complicated HSP received a physiotherapy intervention that included strengthening of the leg muscles and treadmill training for 1 h per session, three to four times a week for 6 weeks. Outcome measures included sit‐to‐stand, 10‐m walk, 1‐min walk tests, and gross motor function measures (dimensions D and E). Results: After the intervention, the sit‐to‐stand, 1‐min walk, and 10‐m walk test scores improved by 6.75 times, 2.57 m, and 0.05 m/s, respectively. Furthermore, the gross motor function measure dimensions D and E scores improved by 8% (46%–54%) and 5% (22%–27%), respectively. The gains in each parameter were maintained at the 3‐ and 6‐month and 1‐year follow‐ups. Conclusion: These results suggest that structured physiotherapy programs can benefit the functional rehabilitation of children with complicated HSP. [ABSTRACT FROM AUTHOR]

The patient was referred to us in view of abnormal magnetic resonance imaging (MRI) that was done for headache and backache. I CLCN2 i -related leukoencephalopathy (CC2L) also known as Leukoencephalopathy with ataxia (LKPAT), is a rare autosomal-recessive leukoencephalopathy often presenting with mild and nonspecific neurological symptoms and has characteristic patterns of white matter oedema observed in magnetic resonance imaging (MRI) of the brain.[[1], [3]] To the best of our knowledge, only around 30 cases of CC2L[1] have been reported to date. The blood investigations were normal, whereas the MRI brain showed findings similar to Case-1 (Fig. [Extracted from the article]

Objective: The objective of this study was to investigate the pathogenesis and inheritance pattern of a Chinese Han family with hereditary spastic paraplegia and to retrospectively analyze the characteristics of KIF1A gene variants and related clinical manifestations. Methods: High‐throughput whole‐exome sequencing was performed on members of a Chinese Han family with a clinical diagnosis of hereditary spastic paraplegia, and the sequencing results were validated by Sanger sequencing. Deep high‐throughput sequencing was performed on subjects with suspected mosaic variants. The previously reported pathogenic variant loci of the KIF1A gene with complete data were collected, and the clinical manifestations and characteristics of the pathogenic KIF1A gene variant were analyzed. Results: A pathogenic heterozygous variant located in the neck coil of the KIF1A gene (c.1139G>C, p.Arg380Pro) was identified in the proband and four additional members of the family. It was derived from the de novo low‐frequency somatic‐gonadal mosaicism of the proband's grandmother and had a rate of 10.95%. Interpretation: This study helps us to better understand the pathogenic mode and characteristics of mosaic variants, and to understand the location and clinical characteristics of pathogenic variants in KIF1A. [ABSTRACT FROM AUTHOR]

Background and purpose: Microtubule defects are a common feature in several neurodegenerative disorders, including hereditary spastic paraplegia. The most frequent form of hereditary spastic paraplegia is caused by mutations in the SPG4/SPAST gene, encoding the microtubule severing enzyme spastin. To date, there is no effective therapy available but spastin‐enhancing therapeutic approaches are emerging; thus prognostic and predictive biomarkers are urgently required. Methods: An automated, simple, fast and non‐invasive cell imaging‐based method was developed to quantify microtubule cytoskeleton organization changes in lymphoblastoid cells and peripheral blood mononuclear cells. Results: It was observed that lymphoblastoid cells and peripheral blood mononuclear cells from individuals affected by SPG4‐hereditary spastic paraplegia show a polarized microtubule cytoskeleton organization. In a pilot study on freshly isolated peripheral blood mononuclear cells, our method discriminates SPG4‐hereditary spastic paraplegia from healthy donors and other hereditary spastic paraplegia subtypes. In addition, it is shown that our method can detect the effects of spastin protein level changes. Conclusions: These findings open the possibility of a rapid, non‐invasive, inexpensive test useful to recognize SPG4‐hereditary spastic paraplegia subtype and evaluate the effects of spastin‐enhancing drug in non‐neuronal cells. [ABSTRACT FROM AUTHOR]

This study investigated the reliability of 3‐dimensional freehand ultrasound (3DfUS) to quantify the size (muscle volume [MV] and anatomical cross‐sectional area [aCSA]), length (muscle length [ML], tendon length [TL], and muscle tendon unit length [MTUL]), and echo‐intensity (EI, whole muscle and 50% aCSA), of lower limb muscles in children with spastic cerebral palsy (SCP) and typical development (TD). In total, 13 children with SCP (median age 14.3 (7.3) years) and 13 TD children (median age 11.1 (1.7) years) participated. 3DfUS scans of rectus femoris, semitendinosus, medial gastrocnemius, and tibialis anterior were performed by two raters in two sessions. The intra‐ and inter‐rater and intra‐ and inter‐session reliability were defined with relative and absolute reliability measures, that is, intra‐class correlation coefficients (ICCs) and absolute and relative standard error of measurement (SEM and SEM%), respectively. Over all conditions, ICCs for muscle size measures ranged from 0.818 to 0.999 with SEM%s of 12.6%–1.6%. For EI measures, ICCs varied from 0.233 to 0.967 with SEM%s of 15.6%–1.7%. Length measure ICCs ranged from 0.642 to 0.999 with SEM%s of 16.0%–0.5%. In general, reliability did not differ between the TD and SCP cohort but the influence of different muscles, raters, and sessions was not constant for all 3DfUS parameters. Muscle length and muscle tendon unit length were the most reliable length parameters in all conditions. MV and aCSA showed comparable SEM%s over all muscles, where tibialis anterior MV was most reliable. EI had low‐relative reliability, but absolute reliability was better, with better reliability for the distal muscles in comparison to the proximal muscles. Combining these results with earlier studies describing muscle morphology assessed in children with SCP, 3DfUS seems sufficiently reliable to determine differences between cohorts and functional levels. The applicability on an individual level, for longitudinal follow‐up and after interventions is dependent on the investigated muscle and parameter. Moreover, the semitendinosus, the acquisition, and processing of multiple sweeps, and the definition of EI and TL require further investigation. In general, it is recommended, especially for longitudinal follow‐up studies, to keep the rater the same, while standardizing acquisition settings and positioning of the subject. [ABSTRACT FROM AUTHOR]

Copy number variations (CNV) may represent a significant proportion of SPG4 and SPG3A diagnosis, the most frequent autosomal dominant subtypes of hereditary spastic paraplegias (HSP). We aimed to assess the frequency of CNVs in SPAST and ATL1 and to update the molecular epidemiology of HSP families in southern Brazil. A cohort study that included 95 Brazilian index cases with clinical suspicion of HSP was conducted between April 2011 and September 2022. Multiplex Ligation Dependent Probe Amplification (MLPA) was performed in 41 cases without defined diagnosis by different massive parallel sequencing techniques (MPS). Diagnosis was obtained in 57/95 (60%) index cases, 15/57 (26.3%) being SPG4. Most frequent autosomal recessive HSP subtypes were SPG7 followed by SPG11, SPG76 and cerebrotendinous xanthomatosis. No CNVs in SPAST and ATL1 were found. Copy number variations are rare among SPG4 and SPG3A families in Brazil. Considering the possibility of CNVs detection by specific algorithms with MPS data, we consider that this is likely the most cost‐effective approach to investigate CNVs in these genes in low‐risk populations, with MLPA being reserved as an orthogonal confirmatory test. [ABSTRACT FROM AUTHOR]