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Hereditary spastic paraplegia (HSP) is a heterogeneous group of neurological disorders that are characterized by progressive spasticity and weakness in the lower limbs. SPG26 is a complicated form of HSP, which includes not only weakness in the lower limbs, but also cognitive impairment, developmental delay, cerebellar ataxia, dysarthria, and peripheral neuropathy, and is caused by biallelic mutations in the B4GALNT1 (beta-1,4-N-acetylgalactosaminyltransferase 1) gene. The B4GALNT1 gene encodes ganglioside GM2/GD2 synthase (GM2S), which catalyzes the transfer of N-acetylgalactosamine to lactosylceramide, GM3, and GD3 to generate GA2, GM2, and GD2, respectively. The present study attempted to characterize a novel B4GALNT1 variant (NM_001478.5:c.937G>A p.Asp313Asn) detected in a patient with progressive multi-system neurodegeneration as well as deleterious variants found in the general population in Japan. Peripheral blood T cells from our patient lacked the ability for activation-induced ganglioside expression assessed by cell surface cholera toxin binding. Structural predictions suggested that the amino acid substitution, p.Asp313Asn, impaired binding to the donor substrate UDP-GalNAc. An in vitro enzyme assay demonstrated that the variant protein did not exhibit GM2S activity, leading to the diagnosis of HSP26. This is the first case diagnosed with SPG26 in Japan. We then extracted 10 novel missense variants of B4GALNT1 from the whole-genome reference panel jMorp (8.3KJPN) of the Tohoku medical megabank organization, which were predicted to be deleterious by Polyphen-2 and SIFT programs. We performed a functional evaluation of these variants and demonstrated that many showed perturbed subcellular localization. Five of these variants exhibited no or significantly decreased GM2S activity with less than 10% activity of the wild-type protein, indicating that they are carrier variants for HSP26. These results provide the basis for molecular analyses of B4GALNT1 variants present in the Japanese population and will help improve the molecular diagnosis of patients suspected of having HSP. [ABSTRACT FROM AUTHOR]

Tubulinopathies are associated with malformations of cortical development but not Walker–Warburg Syndrome. Intensive monitoring of a Croatian infant presenting as Walker–Warburg Syndrome in utero began at 21 weeks due to increased growth of cerebral ventricles and foetal biparietal diameter. Monitoring continued until Caesarean delivery at 34 weeks where the infant was eutrophic. Clinical assessment of a progressive neurological disorder of unknown aetiology found a macrocephalic head and markedly hypoplastic genitalia with a micropenis. Neurological examination showed generalized hypotonia with very rare spontaneous movements, hypotonia-induced respiratory insufficiency and ventilator dependence, and generalized myoclonus intensifying during manipulation. With clinical features of hypotonia, lissencephaly, and brain malformations, Walker–Warburg Syndrome was suspected; however, eye anomalies were absent. Genetic trio analysis via whole-exome sequencing only identified a novel de novo mutation in the TUBA1A gene (NM_006009.4:c.848A>G; NP_006000.2:p.His283Arg) in the infant, who died at 2 months of age, as the likely cause. We report a previously unpublished, very rare heterozygous TUBA1A mutation with clinical features of macrocephaly and hypoplastic genitalia which have not previously been associated with the gene. The absence of eye phenotypes or mutations in Walker–Warburg-associated genes confirm this as not a new presentation of Walker–Warburg Syndrome but a novel TUBA1A tubulinopathy for neonatologists to be aware of. [ABSTRACT FROM AUTHOR]

Motor neuron disorders comprise a clinically and pathologically heterogeneous group of neurologic diseases characterized by progressive degeneration of motor neurons (including both sporadic and hereditary diseases), affecting the upper motor neurons, lower motor neurons, or both. Hereditary motor neuron disorders themselves represent a vast and heterogeneous group, with numerous clinical and genetic overlaps that can be a source of error. This narrative review aims at providing an overview of the main types of inherited motor neuron disorders by recounting the stages in their historical descriptions. For practical purposes, this review of the literature sets out their various clinical characteristics and updates the list of all the genes involved in the various forms of inherited motor neuron disorders, including spinal muscular atrophy, familial amyotrophic lateral sclerosis, hereditary spastic paraplegia, distal hereditary motor neuropathies/neuronopathies, Kennedy's disease, riboflavin transporter deficiencies, VCPopathy and the neurogenic scapuloperoneal syndrome. [ABSTRACT FROM AUTHOR]

Selenoprotein I (SELENOI) catalyzes the final reaction of the CDP-ethanolamine branch of the Kennedy pathway, generating the phospholipids phosphatidylethanolamine (PE) and plasmenyl-PE. Plasmenyl-PE is a key component of myelin and is characterized by a vinyl ether bond that preferentially reacts with oxidants, thus serves as a sacrificial antioxidant. In humans, multiple loss-of-function mutations in genes affecting plasmenyl-PE metabolism have been implicated in hereditary spastic paraplegia, including SELENOI. Herein, we developed a mouse model of nervous system-restricted SELENOI deficiency that circumvents embryonic lethality caused by constitutive deletion and recapitulates phenotypic features of hereditary spastic paraplegia. Resulting mice exhibited pronounced alterations in brain lipid composition, which coincided with motor deficits and neuropathology including hypomyelination, elevated reactive gliosis, and microcephaly. Further studies revealed increased lipid peroxidation in oligodendrocyte lineage cells and disrupted oligodendrocyte maturation both in vivo and in vitro. Altogether, these findings detail a critical role for SELENOI-derived plasmenyl-PE in myelination that is of paramount importance for neurodevelopment. [ABSTRACT FROM AUTHOR]

Rare diseases are predominantly genetic or inherited, and patients with these conditions frequently exhibit neurological symptoms. Diagnosing and treating many rare diseases is a complex challenge, and their low prevalence complicates the performance of research, which in turn hinders the advancement of therapeutic options. One strategy to address this issue is the creation of national or international registries for rare diseases, which can help researchers monitor and investigate their natural progression. In the Republic of Korea, we established a registry across 5 centers that focuses on 3 rare diseases, all of which are characterized by gait disturbances resulting from motor system dysfunction. The registry will collect clinical information and human bioresources from patients with amyotrophic lateral sclerosis, spinocerebellar ataxia, and hereditary spastic paraplegia. These resources will be stored at ICreaT and the National Biobank of Korea. Once the registry is complete, the data will be made publicly available for further research. Through this registry, our research team is dedicated to identifying genetic variants that are specific to Korean patients, uncovering biomarkers that show a strong correlation with clinical symptoms, and leveraging this information for early diagnosis and the development of treatments. [ABSTRACT FROM AUTHOR]

International consortia, novel sequencing techniques, and variant interpretation tools continue to drive genetic discoveries. Current genetic research increasingly exposes loci with phenotypical spectra (locus pleiotropy) in rare inherited neurological disorders. We illustrate this notion through overlaps between inherited peripheral neuropathies, hereditary spastic paraplegias, and spinocerebellar ataxias. The growing awareness of this genetic overlap strains historically defined (clinical) classifications but reveals vulnerable loci and key cellular processes. Enhanced focus on pathomechanisms and uniting cohorts of patients with different neurogenetic disorders could increase effectiveness of diagnosis, scientific discovery, and therapy design. International consortia collaborating on the genetics of rare diseases have significantly boosted our understanding of inherited neurological disorders. Historical clinical classification boundaries were drawn between disorders with seemingly different etiologies, such as inherited peripheral neuropathies (IPNs), spastic paraplegias, and cerebellar ataxias. These clinically defined borders are being challenged by the identification of mutations in genes displaying wide phenotypic spectra and by shared pathomechanistic themes, which are valuable indications for therapy development. We highlight common cellular alterations that underlie this genetic landscape, including alteration of cytoskeleton, axonal transport, mitochondrial function, and DNA repair response. Finally, we discuss venues for future research using the long axonopathies of the PNS as a model to explore other neurogenetic disorders. [ABSTRACT FROM AUTHOR]

Hereditary spastic paraplegia is a neurological condition characterized by predominant axonal degeneration in long spinal tracts, leading to weakness and spasticity in the lower limbs. The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme SARM1 has emerged as a key executioner of axonal degeneration upon nerve transection and in some neuropathies. An increase in the nicotinamide mononucleotide/NAD+ ratio activates SARM1, causing catastrophic NAD+ depletion and axonal degeneration. However, the role of SARM1 in the pathogenesis of hereditary spastic paraplegia has not been investigated. Here, we report an enhanced mouse model for hereditary spastic paraplegia caused by mutations in SPG7. The eSpg7 knockout mouse carries a deletion in both Spg7 and Afg3l1 , a redundant homologue expressed in mice but not in humans. The eSpg7 knockout mice recapitulate the phenotypic features of human patients, showing progressive symptoms of spastic-ataxia and degeneration of axons in the spinal cord as well as the cerebellum. We show that the lack of SPG7 rewires the mitochondrial proteome in both tissues, leading to an early onset decrease in mito-ribosomal subunits and a remodelling of mitochondrial solute carriers and transporters. To interrogate mechanisms leading to axonal degeneration in this mouse model, we explored the involvement of SARM1. Deletion of SARM1 delays the appearance of ataxic signs, rescues mitochondrial swelling and axonal degeneration of cerebellar granule cells and dampens neuroinflammation in the cerebellum. The loss of SARM1 also prevents endoplasmic reticulum abnormalities in long spinal cord axons, but does not halt the degeneration of these axons. Our data thus reveal a neuron-specific interplay between SARM1 and mitochondrial dysfunction caused by lack of SPG7 in hereditary spastic paraplegia. [ABSTRACT FROM AUTHOR]

Parkinsonism is a syndrome characterized by bradykinesia in combination with either rest tremor, rigidity, or both. These features are the cardinal manifestations of Parkinson's disease, the most common cause of parkinsonism, and atypical parkinsonian disorders. However, parkinsonism can be a manifestation of complex neurological and neurodegenerative genetically determined disorders, which have a vast and heterogeneous motor and non-motor phenotypic features. Hereditary dementias, adult-onset ataxias and spastic paraplegias represent only few of this vast group of neurogenetic diseases. This review will provide an overview of parkinsonism's clinical features within adult-onset neurogenetic diseases which a neurologist could face with. Understanding parkinsonism and its characteristics in the context of the aforementioned neurological conditions may provide insights into pathophysiological mechanisms and have important clinical implications, including diagnostic and therapeutic aspects. [ABSTRACT FROM AUTHOR]

Background: Traumatic spinal cord injury (SCI) is a neurological disorder that causes a traumatic anatomical discontinuity of the spinal cord. SCI can lead to paraplegia, spastic, or motor impairments. Go-karting for people with SCI is an adapted sport that is becoming increasingly popular. The purpose of this case report is to shed light on the effects of driving a go-kart on a patient with SCI-related spasticity and to deepen understanding of the possible related role of whole-body vibration (WBV) and neuroendocrine reaction. Methods: The patient was a 50-year-old male with a spastic paraplegia due to traumatic SCI. He regularly practiced go-kart racing, reporting a transient reduction in spasticity. He was evaluated before (T0), immediately after (T1), 2 weeks after (T2), and 4 weeks after (T3) a go-kart driving session. On both sides, long adductor, femoral bicep, and medial and lateral gastrocnemius spasticity was assessed using the Modified Ashworth Scale (MAS), and tone and stiffness were assessed using MyotonPro. Results: It was observed that a go-kart driving session could reduce muscle spasticity, tone, and stiffness. Conclusions: Go-kart driving can be a valid tool to obtain results similar to those of WBV and hormone production in the reduction of spasticity. [ABSTRACT FROM AUTHOR]

Spastic paraplegia 50 (SPG50) is an ultrarare childhood-onset neurological disorder caused by biallelic loss-of-function variants in the AP4M1 gene. SPG50 is characterized by progressive spastic paraplegia, global developmental delay, and subsequent intellectual disability, secondary microcephaly, and epilepsy. We preformed preclinical studies evaluating an adeno-associated virus (AAV)/AP4M1 gene therapy for SPG50 and describe in vitro studies that demonstrate transduction of patient-derived fibroblasts with AAV2/AP4M1, resulting in phenotypic rescue. To evaluate efficacy in vivo, Ap4m1-KO mice were intrathecally (i.t.) injected with 5 × 1011, 2.5 × 1011, or 1.25 × 1011 vector genome (vg) doses of AAV9/AP4M1 at P7–P10 or P90. Age- and dose-dependent effects were observed, with early intervention and higher doses achieving the best therapeutic benefits. In parallel, three toxicology studies in WT mice, rats, and nonhuman primates (NHPs) demonstrated that AAV9/AP4M1 had an acceptable safety profile up to a target human dose of 1 × 1015 vg. Of note, similar degrees of minimalto-mild dorsal root ganglia (DRG) toxicity were observed in both rats and NHPs, supporting the use of rats to monitor DRG toxicity in future i.t. AAV studies. These preclinical results identify an acceptably safe and efficacious dose of i.t.-administered AAV9/AP4M1, supporting an investigational gene transfer clinical trial to treat SPG50. [ABSTRACT FROM AUTHOR]

• NMNAT1 , a key enzyme for NAD+ synthesis , roles in the maintenance of NAD homeostasis of neurons. • Mutations in NMNAT1 cause syndromic and non-syndromic Leber congenital amaurosis-type 9 (LCA9). • For the first time, a probable association between a NMNAT1 variant and HSP disease is detected. • It seems NMNAT1 mutations can present phenotypic heterogeneity. • Phenotypic heterogeneity has already been reported in HSP cases with mutations in other genes. In the NAD biosynthetic network, the nicotinamide mononucleotide adenylyltransferase (NMNAT) enzyme fuels NAD as a co-substrate for a group of enzymes. Mutations in the nuclear-specific isoform, NMNAT1 , have been extensively reported as the cause of Leber congenital amaurosis-type 9 (LCA9). However, there are no reports of NMNAT1 mutations causing neurological disorders by disrupting the maintenance of physiological NAD homeostasis in other types of neurons. In this study, for the first time, the potential association between a NMNAT1 variant and hereditary spastic paraplegia (HSP) is described. Whole-exome sequencing was performed for two affected siblings diagnosed with HSP. Runs of homozygosity (ROH) were detected. The shared variants of the siblings located in the homozygosity blocks were selected. The candidate variant was amplified and Sanger sequenced in the proband and other family members. Homozygous variant c.769G> A :p.(Glu257Lys) in NMNAT1 , the most common variant of NMNAT1 in LCA9 patients, located in the ROH of chromosome 1, was detected as a probable disease-causing variant. After detection of the variant in NMNAT1 , as a LCA9-causative gene, ophthalmological and neurological re-evaluations were performed. No ophthalmological abnormality was detected and the clinical manifestations of these patients were completely consistent with pure HSP. No NMNAT1 variant had ever been previously reported in HSP patients. However, NMNAT1 variants have been reported in a syndromic form of LCA which is associated with ataxia. In conclusion, our patients expand the clinical spectrum of NMNAT1 variants and represent the first evidence of the probable correlation between NMNAT1 variants and HSP. [ABSTRACT FROM AUTHOR]

Background: Stroke and spinal cord injury are neurological disorders that cause disability and exert tremendous social and economic effects. Robot-assisted training (RAT), which may reduce spasticity, is widely applied in neurorehabilitation. The combined effects of RAT and antispasticity therapies, such as botulinum toxin A injection therapy, on functional recovery remain unclear. This review evaluated the effects of combined therapy on functional recovery and spasticity reduction. Materials and Methods: Studies evaluating the efficacy of RAT and antispasticity therapy in promoting functional recovery and reducing spasticity were systemically reviewed. Five randomized controlled trials (RCTs) were included. The modified Jadad scale was applied for quality assessment. Functional assessments, such as the Berg Balance Scale, were used to measure the primary outcome. Spasticity assessments, such as the modified Ashworth Scale, were used to measure the secondary outcome. Results: Combined therapy improves functional recovery in the lower limbs but does not reduce spasticity in the upper or lower limbs. Conclusions: The evidence supports that combined therapy improves lower limb function but does not reduce spasticity. The considerable risk of bias among the included studies and the enrolled patients who did not receive interventions within the golden period of intervention are two major factors that should be considered when interpreting these results. Additional high-quality RCTs are required. [ABSTRACT FROM AUTHOR]

The Parkinson's disease-amyotrophic lateral sclerosis (ALS) complex typically manifests as levodopa-responsive parkinsonism, followed by ALS. It is extremely rare for Parkinson's disease and ALS to coexist without other neurological disorders. Named after the scientists who first described this overlap of two neurodegenerative conditions, it is referred to as Brait-Fahn-Schwartz disease. Given its variable presentation, increasing rarity, and lack of any diagnostic test, it poses a diagnostic challenge for physicians. We present a case of a 55-year-old Pakistani male experiencing progressive quadriparesis with spastic lower limbs and flaccid upper limbs, in addition to the cardinal features of idiopathic Parkinson's disease. Since there is currently no cure available for either Parkinson's disease or ALS, all available treatment focuses on improving quality of life, which we achieved in our patient. This case is unique in being the first incidence of Parkinson's disease-ALS complex in a novel geographic region such as Pakistan, where genetic testing and cost constraints limit the diagnosis of rare disorders. The coexistence of extrapyramidal symptoms and pyramidal symptoms is uncommon. In such situations, physicians may overlook one group of symptoms, potentially leading to a misdiagnosis. This case highlights the value of a thorough physical examination and electrodiagnostic studies and suggests the association between Parkinson's disease and ALS. This case demonstrates the significance of understanding when Parkinson's disease symptoms start to appear in patients with ALS and the need to start dopaminergic therapy in those who had Parkinson's disease features before ALS to alleviate the suffering of an individual and enhance quality of life. [ABSTRACT FROM AUTHOR]

Objectives: The term hereditary spastic paraplegia comprises an ever-expanding array of neurological disorders with distinct aetiologies. Spastic paraplegia gene 39 is one of the many genetically defined types with features of other organs and neurological systems in addition to paraspasticity. We describe a large kindred with a novel clinical phenotype as, in addition to spastic paraplegia, affected subjects suffered from a prominent cerebellar oculomotor dysfunction with two hitherto undescribed mutations of PNPLA6. Methods: Three of five genetically tested family members of a large kindred were affected by spastic gait and a unique and prominent cerebellar oculomotor dysfunction. Further clinical, imaging, laboratory and videonystagmographic data were analyzed. Genetic analysis was done using next-generation sequencing. Results: The most salient clinical feature, in addition to paraspasticity, in three of five subjects was cerebellar oculomotor dysfunction with an upbeating nystagmus provoked by downward gaze. Genetic analysis revealed two hitherto unknown sequence variants in the PNPLA6 gene, a splice-site variant c.1635 + 3G > T and a missense variant c.3401A > T, p.(Asp1134Val). In addition to cerebellar oculomotor dysfunction, compound-heterozygous siblings presented with paraspasticity and a moderate hypogonadotropic hypogonadism in the female. A paternal uncle being homozygous for the splice-site variant of PNPLA6 presented with increased lower limb reflexes and an unstable gait. Treatment with 4-aminopyridine, a potassium channel blocker, lead to meaningful improvement of clinical symptoms. Conclusions: The unique and prominent cerebellar ocular motor disorder in our family broadens the spectrum of clinical phenotypes associated with variations in the PNLA6 gene. The finding of paraspasticity with cerebellar oculomotor dysfunction alongside inconspicuous brainstem imaging may raise suspicion of complex HSP with PNPLA6 mutations. [ABSTRACT FROM AUTHOR]

Parkinsonism, genetic, imaging, neuronal ceroid lipofuscinosis, CLN5 disease We here report on a patient with adult-onset NCL type 5 with atypical parkinsonism and a pathological DaTSCAN partially responding to dopaminergic treatment. Keywords: neuronal ceroid lipofuscinosis; CLN5 disease; parkinsonism; genetic; imaging EN neuronal ceroid lipofuscinosis CLN5 disease parkinsonism genetic imaging 1116 1119 4 11/07/22 20221101 NES 221101 Neuronal ceroid lipofuscinoses (NCLs) represent severe, commonly autosomal-recessively inherited, progressive neurodegenerative diseases mainly affecting children and young adults.1 To date, there are at least 13 different genes, mutations of which cause various subtypes.2 NCLs commonly show a broad phenotypic spectrum, including continuous loss of vision, various movement disorders, progressive mental deterioration, and seizures. [Extracted from the article]

Magnetic stimulation is a safe, non-invasive diagnostic tool and promising treatment strategy for neurological and psychiatric disorders. Although most studies address transcranial magnetic stimulation, transspinal magnetic stimulation (TsMS) has received recent attention since trials involving invasive spinal cord stimulation showed encouraging results for pain, spasticity, and Parkinson's disease. While the effects of TsMS on spinal roots is well understood, its mechanism of action on the spinal cord is still controversial. Despite unclear mechanisms of action, clinical benefits of TsMS have been reported, including improvements in scales of spasticity, hyperreflexia, and bladder and bowel symptoms, and even supraspinal gait disorders such as freezing and camptocormia. In the present study, a critical review on the application of TsMS in neurology was conducted, along with an exploratory trial involving TsMS in three patients with hereditary spastic paraplegia. The goal was to understand the mechanism of action of TsMS through H-reflex measurement at the unstimulated lumbosacral level. Although limited by studies with a small sample size and a low to moderate effect size, TsMS is safe and tolerable and presents consistent clinical and neurophysiological benefits that support its use in clinical practice. [ABSTRACT FROM AUTHOR]

Objective: Human genomics established that pathogenic variation in diverse genes can underlie a single disorder. For example, hereditary spastic paraplegia is associated with >80 genes, with frequently only few affected individuals described for each gene. Herein, we characterize a large cohort of individuals with biallelic variation in ENTPD1, a gene previously linked to spastic paraplegia 64 (Mendelian Inheritance in Man # 615683). Methods: Individuals with biallelic ENTPD1 variants were recruited worldwide. Deep phenotyping and molecular characterization were performed. Results: A total of 27 individuals from 17 unrelated families were studied; additional phenotypic information was collected from published cases. Twelve novel pathogenic ENTPD1 variants are described (NM 001776.6): c.398_399delinsAA; p.(Gly133Glu), c.540del; p.(Thr181Leufs*18), c.640del; p.(Gly216Glufs*75), c.185 T > G; p.(Leu62*), c.1531 T > C; p.(*511Glnext*100), c.967C > T; p.(Gln323*), c.414‐2_414‐1del, and c.146 A > G; p.(Tyr49Cys) including 4 recurrent variants c.1109 T > A; p.(Leu370*), c.574‐6_574‐3del, c.770_771del; p.(Gly257Glufs*18), and c.1041del; p.(Ile348Phefs*19). Shared disease traits include childhood onset, progressive spastic paraplegia, intellectual disability (ID), dysarthria, and white matter abnormalities. In vitro assays demonstrate that ENTPD1 expression and function are impaired and that c.574‐6_574‐3del causes exon skipping. Global metabolomics demonstrate ENTPD1 deficiency leads to impaired nucleotide, lipid, and energy metabolism. Interpretation: The ENTPD1 locus trait consists of childhood disease onset, ID, progressive spastic paraparesis, dysarthria, dysmorphisms, and white matter abnormalities, with some individuals showing neurocognitive regression. Investigation of an allelic series of ENTPD1 (1) expands previously described features of ENTPD1‐related neurological disease, (2) highlights the importance of genotype‐driven deep phenotyping, (3) documents the need for global collaborative efforts to characterize rare autosomal recessive disease traits, and (4) provides insights into disease trait neurobiology. ANN NEUROL 2022;92:304–321 [ABSTRACT FROM AUTHOR]

Biallelic mutations in POLR3A have been associated with childhood‐onset hypomyelinating leukodystrophies and adolescent‐to‐adult‐onset spastic ataxia, the latter of which has been linked to the intronic variant c.1909 + 22G>A. We report a case of adult‐onset spastic ataxia in a 75‐year‐old man, being a compound heterozygous carrier of this variant, whose brain and spinal cord were for the first time investigated by neuropathological examination. We describe prominent degeneration of the posterior columns, spinocerebellar tracts, and anterior corticospinal tracts of the spinal cord in a pattern resembling Friedreich's ataxia, with a notable lack of significant white matter pathology throughout the brain, in marked contrast with childhood‐onset cases. Immunohistochemical examination for the POLR3A protein demonstrated no apparent differences in localization or staining intensity between the proband and an age‐matched control subject. We demonstrate the clinicopathologic description of POLR3A‐related neurodegenerative disease and also mention the differential diagnosis of the childhood‐onset hypomyelinating leukodystrophy and late‐onset spastic ataxia phenotypes. [ABSTRACT FROM AUTHOR]

In individuals with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), spasticity is one of the main symptoms. The neurological signs of the disease are well defined, but details of how spasticity appears in these individuals have not been well explored. To describe spasticity location and severity of HAM/TSP individuals. Cross-sectional study with individuals older than 18 years, diagnosed with HAM/TSP and with lower limb spasticity. Pregnant women, individuals with other associated neurological diseases, and those using antispastic drugs were not included. Spasticity was assessed by the Modified Ashworth Scale (MAS), applied to the abductor, adductor, flexor, and extensor muscles of the hips, flexors, and extensors of the knees, dorsiflexors, plantiflexors, evertors, and inverters of the foot. Thirty participants were included. The plantiflexor muscles (90%), knee extensors (80%), knee flexors (63,3%), and adductors (50%) were most frequently affected by spasticity. Twenty-three (76.7%) individuals had mixed spasticity, 5 (16.7%) with distal spasticity and 2 (6.7%) with proximal spasticity. MAS was similar between the lower limbs in at least 6 of the 10 muscle groups of each individual. Spasticity was mostly mixed in the lower limbs, with more frequently mild severity. The individuals were partially symmetrical between the lower limbs. The most affected muscle groups were the plantiflexors, knee extensors and flexors and the hip adductors, consecutively, being predominantly symmetrical. [ABSTRACT FROM AUTHOR]

Primary familial brain calcification (PFBC) is a progressive neurological disorder manifesting as bilateral brain calcifications in CT scan with symptoms as parkinsonism, dystonia, ataxia, psychiatric symptoms, etc. Recently, pathogenic variants in MYORG have been linked to autosomal recessive PFBC. This study aims to elucidate the mutational and clinical spectrum of MYORG mutations in a large cohort of Chinese PFBC patients with possible autosomal recessive or absent family history. Mutational analyses of MYORG were performed by Sanger sequencing in a cohort of 245 PFBC patients including 21 subjects from 10 families compatible with a possibly autosomal-recessive trait and 224 apparently sporadic cases. In-depth phenotyping and neuroimaging features were investigated in all patients with novel MYORG variants. Two nonsense variants (c.442C > T, p. Q148*; c.972C > A, p. Y324*) and two missense variants (c.1969G>C, p. G657R; c.2033C > G, p. P678R) of MYORG were identified in four sporadic PFBC patients, respectively. These four novel variants were absent in gnomAD, and their amino acid were highly conserved, suggesting these variants have a pathogenic impact. Patients with MYORG variants tend to display a homogeneous clinical spectrum, showing extensive brain calcification and parkinsonism, dysarthria, ataxia, or vertigo. Our findings supported the pathogenic role of MYORG variants in PFBC and identified two pathogenic variants (c.442C > T, c.972C > A), one likely pathogenic variant (c.2033C > G), and one variant of uncertain significance (c.1969G>C), further expanding the genetic and phenotypic spectrum of PFBC- MYORG. [ABSTRACT FROM AUTHOR]

SPG76 is one of the rare forms of hereditary spastic paraplegia (HSP) which causes by mutations in the CAPN1 gene. The mode of inheritance of SPG76 is autosomal recessive (AR) and so far, only 24 families and 25 mutations in this gene have been reported worldwide. These mutations have been associated with a spectrum of disorders from pure HSP to spastic ataxia. HSP genetically is one of the most heterogeneous neurological disorders and to date, 79 types of HSP (SPG1-SPG79) have been identified, however, it has been suggested that many HSP-genes, particularly in AR-HSPs, remained unknown. AR-HSPs clinically overlap with other neurodegenerative disorders, making an accurate diagnosis of the disease difficult. Therefore, in addition to clinical examination, a high throughout genetic method like whole exome sequencing (WES) may be necessary for the diagnosis of this type of neurodegenerative disorders. Herein, we present the clinical features and results of WES in the first Iranian family with a novel CAPN1 variant, c.C853T:p.R285* and pure HSP. Some of the previous studies have mentioned that the "spasticity-ataxia phenotype might be conducted to the diagnosis of SPG76" but recently the number of pure HSP patients with CAPN1 mutation is increasing. The present study also expands the mutation spectrum of pure CAPN1-related SPG76; emphasizing that CAPN1 screening is required in both pure HSP and spasticity-ataxia phenotypes. As noted in some other literature, we suggest the clinical spectrum of this disorder to be considered as "CAPN1-associated neurodegeneration". [ABSTRACT FROM AUTHOR]

Keywords: VPS13D; phenotype-genotype correlation EN VPS13D phenotype-genotype correlation 803 806 4 07/21/21 20210701 NES 210701 Here, we report two siblings with compound heterozygous variants in I VPS13D i but a considerable divergent phenotype highlighting the difficulties of phenotype-genotype correlation in this rare disease. In contrast, non-essential splice site/LOF mutations or other mutation type combinations might be associated with a broader and more severe spectrum of phenotypes.2 Given our siblings' identical compound heterozygous I VPS13D i variants and their unlike phenotypes, a specific phenotype-genotype correlation seems questionable. This makes it even more important to be aware of this gene, especially in patients presenting with childhood-onset ataxia-plus syndrome or suspected hereditary spastic paraplegia with or without mental disability. [Extracted from the article]

The article discusses research which evaluated the genetics of hereditary spastic paraplegia (HSP), a rare, clinically heterogenous degenerative neurogenetic disorder.

De novo glycosphingolipid (GSL) biosynthesis defects cause severe neurological diseases, including hereditary sensory and autonomic neuropathy type 1A (HSAN1A), GM3 synthase deficiency, and hereditary spastic paraplegia type 26 (HSPG26), each lacking effective treatment. Recombinant adeno-associated virus (AAV)-mediated gene therapy has emerged as a powerful treatment for monogenic diseases and might be particularly suitable for these neurological conditions. [ABSTRACT FROM AUTHOR]

Background and purpose: Despite enormous advances in identifying genetic variants responsible for many neurological diseases, access to genetic testing may be limited in clinical practice. The objective of this study was to assess worldwide access to genetic tests for movement disorders and factors impacting their utilization. Methods: The Rare Movement Disorders Study Group of the International Parkinson and Movement Disorder Society designed an online survey electronically mailed to all 7815 members. Results: Survey data completed by 1269 participants from 109 countries were analysed. Limited access to geneticists and genetic counsellors was reported in many world regions compared to Europe and North America. Availability of genetic testing was limited, with rates of access lower than 50%. Genetic testing for chorea was the most commonly available. For parkinsonism, dystonia, ataxia, hereditary spastic paraplegias and metabolic disorders, there was limited access to genetic testing in all countries compared to Europe and North America, with significant differences found for Africa, Central/South America, Asia. In many regions, genetic testing was supported by either private or public funding. Genetic testing was free of charge in Europe according to 63.5% of respondents. In North America, Africa, Central/South America, Asia and the Middle East access to free of charge genetic testing was by far significantly lower compared to Europe. Conclusions: This survey highlights difficulties in accessing genetic testing and individuals with expertise in genetics at the worldwide level. In addition, major disparities in genetic testing amongst world regions are highlighted, probably due to a variety of factors including financial barriers. [ABSTRACT FROM AUTHOR]

Human 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) is a putative iron-containing non-heme oxygenase of unknown specificity and biological significance. We report 25 families containing 34 individuals with neurological disease associated with biallelic HPDL variants. Phenotypes ranged from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spasticity and global developmental delays, sometimes complicated by episodes of neurological and respiratory decompensation. Variants included bona fide pathogenic truncating changes, although most were missense substitutions. Functionality of variants could not be determined directly as the enzymatic specificity of HPDL is unknown; however, when HPDL missense substitutions were introduced into 4-hydroxyphenylpyruvate dioxygenase (HPPD, an HPDL orthologue), they impaired the ability of HPPD to convert 4-hydroxyphenylpyruvate into homogentisate. Moreover, three additional sets of experiments provided evidence for a role of HPDL in the nervous system and further supported its link to neurological disease: (i) HPDL was expressed in the nervous system and expression increased during neural differentiation; (ii) knockdown of zebrafish hpdl led to abnormal motor behaviour, replicating aspects of the human disease; and (iii) HPDL localized to mitochondria, consistent with mitochondrial disease that is often associated with neurological manifestations. Our findings suggest that biallelic HPDL variants cause a syndrome varying from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spastic tetraplegia associated with global developmental delays. [ABSTRACT FROM AUTHOR]

Some of the key clinical, neuroimaging and (neuro)pathology characteristics that allow I ante-mortem i identification of jNIID and aNIID may not be useful to diagnose iNIID patients. Chen et al.1 have demonstrated lack of abnormal CGG expansions in the I NOTCH2NLC i gene among European juvenile and adult patients with neuronal intranuclear inclusion disease (jNIID and aNIID). IIs in non-neuronal CNS cell types have been unambiguously reported in only one patient (less than 5% of astrocytes contained IIs).8 The extent and distribution of CNS neuronal loss may be variable, however, cerebellar (cortical) atrophy is almost universally present in iNIID patients. [Extracted from the article]

Introduction: This systematic review appraises the measurement quality of tools which assess activity and/or participation in adults with upper limb spasticity arising from neurological impairment, including methodological quality of the psychometric studies. Differences in the measurement quality of the tools for adults with a neurological impairment, but without upper limb spasticity, is also presented. Methods: 29 measurement tools identified in a published review were appraised in this systematic review. For each identified tool, we searched 3 databases (Medline, Embase, CINAHL) to identify psychometric studies completed with neurorehabilitation samples. Methodological quality of instrument evaluations was assessed with use of the Consensus-based Standards for the Selection of Health Status Measurement Instruments (COSMIN) checklist. Synthesis of ratings allowed an overall rating of the psychometric evidence for each measurement tool to be calculated. Results: 149 articles describing the development or evaluation of psychometric properties of 22 activity and/or participation measurement tools were included. Evidence specific to tool use for adults with spasticity was identified within only 15 of the 149 articles and provided evidence for 9 measurement tools only. Overall, COSMIN appraisal highlighted a lack of evidence of measurement quality. Synthesis of ratings demonstrated all measures had psychometric weaknesses or gaps in evidence (particularly for use of tools with adults with spasticity). Conclusions: The systematic search, appraisal and synthesis revealed that currently there is insufficient measurement quality evidence to recommend one tool over another. Notwithstanding this conclusion, newer tools specifically designed for use with people with neurological conditions who have upper limb spasticity, have emergent measurement properties that warrant further research. Systematic review registration: PROSPERO CRD42014013190. [ABSTRACT FROM AUTHOR]

While rare diseases (RDs) are by definition of low prevalence, the total number of patients suffering from an RD is high, and the majority of them have neurologic manifestations, involving central, peripheral nerve, and muscle. In 2017, 24 European Reference Networks (ERNs), each focusing on a specific group of rare or low-prevalence complex diseases, were formed to improve the care for patients with an RD. One major aim is to have "the knowledge travel instead of the patient," which has been put into practice by the implementation of the Clinical Patient Management System (CPMS) that enables clinicians to perform pan-European virtual consultations. The European Reference Network for Rare Neurological Diseases (ERN-RND) provides an infrastructure for knowledge sharing and care coordination for patients affected by a rare neurological disease (RND) involving the most common central nervous system pathological conditions. It covers the following disease groups: (i) Cerebellar Ataxias and Hereditary Spastic Paraplegias; (ii) Huntington's disease and Other Choreas; (iii) Frontotemporal dementia; (iv) Dystonia, (non-epileptic) paroxysmal disorders, and Neurodegeneration with Brain Iron Accumulation; (v) Leukoencephalopathies; and (vi) Atypical Parkinsonian Syndromes. At the moment, it unites 32 expert centers and 10 affiliated partners in 21 European countries, as well as patient representatives, but will soon cover nearly all countries of the European Union as a result of the ongoing expansion process. Disease expert groups developed and consented on diagnostic flowcharts and disease scales to assess the different aspects of RNDs. ERN-RND has started to discuss diagnostically unclear patients in the CPMS, is one of four ERNs that serve as foundation of Solve-RD, and has established an RND training and education program. The network will facilitate trial readiness through the establishment of an ERN-RND registry with a minimal data of all patients seen at the ERN-RND centers, thus providing a unique overview of existing genotype-based cohorts. The overall aim of the ERNs is to improve access for patients with RDs to quality diagnosis, care, and treatment. Based on this objective, ERNs are monitored by the European Commission on a regular basis to provide transparency and reassurance to the RD community and the general public. [ABSTRACT FROM AUTHOR]

Spastic paraplegia-56 is a rare autosomal recessive disorder, caused by homozygous or compound heterozygous mutations in the CYP2U1 gene, located on chromosome 4. Till date, only 28 patients with this disorder have been reported in the literature. We report a new case of CYP2U1-related spastic paraplegia-56. We also reviewed previously published patients with this condition from various databases. Next-generation sequencing in the index child detected a novel homozygous two base pair deletion in exon 2 of the CYP2U1 gene that results in a frameshift and premature truncation of the protein 19 amino-acid downstream to codon 361. Together with the presented case, 29 were available for analysis. The mean age at the diagnosis was 17.84 ± 6.86 years. Intellectual disability/cognitive dysfunction and delayed walking or gait disturbance were the most common presenting features. Around half of the patients had neuroregression in between 1 and 2 years. It is clinically imperative to suspect this disease in children with early-onset spastic paraparesis, especially in cases accompanied by baseline development delay or cognitive impairment and consanguinity. [ABSTRACT FROM AUTHOR]

Purpose: Little is known concerning the impact of chronic spasticity on physical activities, social participation, and well-being, and whether patients' needs are addressed by current treatments. This study aims to investigate these lacunas in persons with a pure form of hereditary spastic paraplegia (HSP), in whom spasticity is a prominent symptom. Methods: Fourteen patients with a pure form of HSP were interviewed. These interviews were recorded, verbally transcribed, and thematically analyzed. Results: Four themes were identified which can be reflected by the phrases: (1) 'I stumble', (2) 'I struggle', (3) 'I feel ashamed', and (4) 'I need support'. Balance and gait problems led to limitations in domestic activities, employment, and recreation. 'Stumbling' also occurred due to pain, stiffness, and fatigue. Struggling was related to the continuous need for adaptation strategies, including the abandonment of some activities. Participants further reported feelings of shame, fear, and frustration. Lastly, they needed more support in daily activities than currently provided. Conclusion: Besides treating spasticity-related motor impairments, patients with HSP need practical support for optimizing their physical activities and social participation. They also seek attention for the non-motor consequences of their chronic spasticity to improve their well-being. Patient-reported outcomes might help to address these needs. According to patients with hereditary spastic paraplegia, interventions for spasticity should not only be aimed at reducing motor impairments, but also on reducing pain and fatigue, improving nighttime rest and general well-being, and optimizing the performance of relevant personal activities. Medical, role and emotional management in patients with hereditary spastic paraplegia can be improved only when individual needs are identified and monitored over the course of the disease. Besides assessment of bodily functions and physical capacities, systematic evaluation of patient-reported outcomes will help both patients and professionals to monitor the functional impact of disease progression and to evaluate the effects of interventions aimed at retarding this progression. [ABSTRACT FROM AUTHOR]

We report bi-allelic pathogenic HPDL variants as a cause of a progressive, pediatric-onset spastic movement disorder with variable clinical presentation. The single-exon gene HPDL encodes a protein of unknown function with sequence similarity to 4-hydroxyphenylpyruvate dioxygenase. Exome sequencing studies in 13 families revealed bi-allelic HPDL variants in each of the 17 individuals affected with this clinically heterogeneous autosomal-recessive neurological disorder. HPDL levels were significantly reduced in fibroblast cell lines derived from more severely affected individuals, indicating the identified HPDL variants resulted in the loss of HPDL protein. Clinical presentation ranged from severe, neonatal-onset neurodevelopmental delay with neuroimaging findings resembling mitochondrial encephalopathy to milder manifestation of adolescent-onset, isolated hereditary spastic paraplegia. All affected individuals developed spasticity predominantly of the lower limbs over the course of the disease. We demonstrated through bioinformatic and cellular studies that HPDL has a mitochondrial localization signal and consequently localizes to mitochondria suggesting a putative role in mitochondrial metabolism. Taken together, these genetic, bioinformatic, and functional studies demonstrate HPDL is a mitochondrial protein, the loss of which causes a clinically variable form of pediatric-onset spastic movement disorder. [ABSTRACT FROM AUTHOR]

The readthrough of premature termination codon (PTC) by ribosome sometimes produces full-length proteins. We previously reported a readthrough of PTC of glycosyltransferase gene B4GALNT1 with hereditary spastic paraplegia (HSP). Here we featured the readthrough of B4GALNT1 of two mutants, M4 and M2 with PTC by immunoblotting and flow cytometry after transfection of B4GALNT1 cDNAs into cells. Immunoblotting showed a faint band of full-length mutant protein of M4 but not M2 at a similar position with that of wild-type B4GALNT1. AGC sequences at immediately before and after the PTC in M4 were critical for the readthrough. Treatment of cells transfected with mutant M4 cDNA with aminoglycosides resulted in increased readthrough of PTC. Furthermore, treatment of transfectants of mutant M2 cDNA with G418 also resulted in the induction of readthrough of PTC. Both M4 and M2 cDNA transfectants showed increased/induced bands in immunoblotting and GM2 expression in a dose-dependent manner of aminoglycosides. Results of mass spectrometry supported this effect. Here, we showed for the first time the induction and/or enhancement of the readthrough of PTCs of B4GALNT1 by aminoglycoside treatment, suggesting that aminoglycosides are efficient for patients with HSP caused by PTC of B4GALNT1 , in which gradual neurological disorders emerged with aging. [ABSTRACT FROM AUTHOR]