Search

There are more than 10,000 individual rare diseases and most are without therapy. Personalized genetic therapy represents one promising approach for their treatment. We present a road map for individualized treatment of an ultra-rare disease by establishing a gene replacement therapy developed for a single patient with hereditary spastic paraplegia type 50 (SPG50). Through a multicenter collaboration, an adeno-associated virus-based gene therapy product carrying the AP4M1 gene was created and successfully administered intrathecally to a 4-year-old patient within 3 years of diagnosis as part of a single-patient phase 1 trial. Primary endpoints were safety and tolerability, and secondary endpoints evaluated efficacy. At 12 months after dosing, the therapy was well tolerated. No serious adverse events were observed, with minor events, including transient neutropenia and Clostridioides difficile gastroenteritis, experienced but resolved. Preliminary efficacy measures suggest a stabilization of the disease course. Longer follow-up is needed to confirm the safety and provide additional insights on the efficacy of the therapy. Overall, this report supports the safety of gene therapy for SPG50 and provides insights into precision therapy development for rare diseases. Clinical trial registration: NCT06069687 .

To the Editor: The hereditary spastic paraplegias (HSPs) are a group of more than 80 neurogenetic disorders that share the feature of progressive lower limb spasticity. Biallelic loss-of-function variants in [...]

Juvenile‐onset Huntington's disease (HD) is a rare subset of HD with symptom‐onset before the age of 18. In contrast to the adult population, children present early‐on with behavioral, psychiatric, and cognitive symptoms, in addition to a diverse spectrum of movement disorders. This poses a distinct challenge in diagnosis and management. We here describe the spectrum of movement disorders, accompanied with detailed video recordings, in seven cases of juvenile‐onset HD. Our findings highlight early cognitive and behavioral symptoms, preceding motor symptoms. The diverse movement disorder phenotypes included dystonia, Parkinsonism, myoclonus, and chorea, findings which underscore the heterogeneity of presenting symptoms. [ABSTRACT FROM AUTHOR]

Background: The GCH1 gene encodes the enzyme guanosine triphosphate cyclohydrolase I (GTPCH), which catalyzes the rate‐limiting step in the biosynthesis of tetrahydrobiopterin (BH4), a critical cofactor in the production of monoamine neurotransmitters. Autosomal dominant GTPCH (adGTPCH) deficiency is the most common cause of dopa‐responsive dystonia (DRD), whereas the recessive form (arGTPCH) is an ultrarare and poorly characterized disorder with earlier and more complex presentation that may disrupt neurodevelopmental processes. Here, we delineated the phenotypic spectrum of ARGTPCHD and investigated the predictive value of biochemical and genetic correlates for disease outcome. Objectives: The aim was to study 4 new cases of arGTPCH deficiency and systematically review patients reported in the literature. Methods: Clinical, biochemical, and genetic data and treatment response of 45 patients are presented. Results: Three phenotypes were outlined: (1) early‐infantile encephalopathic phenotype with profound disability (24 of 45 patients), (2) dystonia‐parkinsonism phenotype with infantile/early‐childhood onset of developmental stagnation/regression preceding the emergence of movement disorder (7 of 45), and (3) late‐onset DRD phenotype (14 of 45). All 3 phenotypes were responsive to pharmacological treatment, which for the first 2 must be initiated early to prevent disabling neurodevelopmental outcomes. A gradient of BH4 defect and genetic variant severity characterizes the 3 clinical subgroups. Hyperphenylalaninemia was not observed in the second and third groups and was associated with a higher likelihood of intellectual disability. Conclusions: The clinical spectrum of arGTPCH deficiency is a continuum from early‐onset encephalopathies to classical DRD. Genotype and biochemical alterations may allow early diagnosis and predict clinical severity. Early treatment remains critical, especially for the most severe patients. [ABSTRACT FROM AUTHOR]

Status dystonicus is the most severe form of dystonia with life‐threatening complications if not treated promptly. We present consensus recommendations for the initial management of acutely worsening dystonia (including pre–status dystonicus and status dystonicus), as well as refractory status dystonicus in children. This guideline provides a stepwise approach to assessment, triage, interdisciplinary treatment, and monitoring of status dystonicus. The clinical pathways aim to: (1) facilitate timely recognition/triage of worsening dystonia, (2) standardize supportive and dystonia‐directed therapies, (3) provide structure for interdisciplinary cooperation, (4) integrate advances in genomics and neuromodulation, (5) enable multicenter quality improvement and research, and (6) improve outcomes. © 2024 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Background Cases Conclusions The Powassan virus is a rare neurotropic, tick‐borne arbovirus associated with meningoencephalitis. Despite the virus's known predilection for the basal ganglia, there are no reports detailing the spectrum of movement disorders in children with Powassan meningoencephalitis.We present 3 cases of pediatric Powassan encephalitis, highlighting the diverse and evolving movement disorders associated with this disease. We observed subcortical myoclonus and progressive generalized dystonia (patient 1), transient dyskinesias and refractory focal dystonia (patient 2), and generalized dystonia evolving into chorea and lingual dyskinesias (patient 3). One patient exhibited multifocal vasculitis on magnetic resonance imaging angiography, a novel finding.Movement disorders were a primary source of the morbidity experienced by pediatric Powassan encephalitis patients throughout their disease course, underscoring the importance of regular monitoring and adaptable treatment strategies in this condition. Larger, prospective studies are necessary to fully delineate the spectrum of associated movement disorders in this rare and severe disease. [ABSTRACT FROM AUTHOR]

This article discusses a case report of a 6-year-old female with childhood-onset pure hereditary spastic paraplegia (HSP) caused by biallelic variants in the COQ4 gene. HSP is a genetically and clinically diverse condition characterized by lower limb spasticity and weakness. The patient's symptoms included progressive lower limb spasticity, delayed motor development, and the need for assistive devices for walking. Genetic testing confirmed the presence of two variants in the COQ4 gene, one of which has been associated with severe phenotypes. This case expands the understanding of COQ4-associated HSP and highlights the importance of genetic testing in diagnosing the condition. The text also discusses the association between COQ4 deficiency and hereditary spastic paraplegia (HSP), a neurological disorder characterized by progressive stiffness and weakness in the legs. The text describes several variants of COQ4 deficiency found in Chinese families, some of which also involve epilepsy and vision impairment. The age at onset of symptoms varies, and functional studies have shown reduced levels of CoQ10 in patients with COQ4 deficiency. The text emphasizes the importance of reanalyzing genetic data and highlights the potential therapeutic implications of supplementing CoQ10. [Extracted from the article]

Macroautophagy is a highly conserved cellular pathway for the degradation and recycling of defective cargo including proteins, organelles, and macromolecular complexes. As autophagy is particularly relevant for cellular homeostasis in post-mitotic tissues, congenital disorders of autophagy, due to monogenic defects in key autophagy genes, share a common "clinical signature" including neurodevelopmental, neurodegenerative, and neuromuscular features, as well as variable abnormalities of the eyes, skin, heart, bones, immune cells, and other organ systems, depending on the expression pattern and the specific function of the defective proteins. Since the clinical and genetic resolution of EPG5-related Vici syndrome, the paradigmatic congenital disorder of autophagy, the widespread use of massively parallel sequencing has resulted in the identification of a growing number of autophagy-associated disease genes, encoding members of the core autophagy machinery as well as related proteins. Recently identified monogenic disorders linking selective autophagy, vesicular trafficking, and other pathways have further expanded the molecular and phenotypical spectrum of congenital disorders of autophagy as a clinical disease spectrum. Moreover, significant advances in basic research have enhanced the understanding of the underlying pathophysiology as a basis for therapy development. Here, we review (i) autophagy in the context of other intracellular trafficking pathways; (ii) the main congenital disorders of autophagy and their typical clinico-pathological signatures; and (iii) the recommended primary health surveillance in monogenic disorders of autophagy based on available evidence. We further discuss recently identified molecular mechanisms that inform the current understanding of autophagy in health and disease, as well as perspectives on future therapeutic approaches., (© 2024 The Author(s). Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

Frataxin is an evolutionarily conserved mitochondrial protein responsible for iron homeostasis and metabolism. A deficiency of frataxin (encoded by FXN) leads to Friedreich's ataxia (FRDA), a progressive disorder that affects both the central and peripheral nervous systems, most commonly via a pathogenic GAA trinucleotide expansion. In contrast, pathogenic variants in ALG1 in humans cause a form of congenital disorder of glycosylation. Here, we present a 15-year-old boy with a clinical presentation that raised concern for complex hereditary spastic paraplegia (HSP), with motor features including progressive spastic paraparesis, cervical dystonia, cerebellar dysfunction, and diminished lower extremity reflexes. The proband was initially found to have a novel compound heterozygous variant in ALG1 on exome sequencing, along with N-glycan profiling revealing evidence of defective mannosylation and Western blot analysis demonstrating an 84% reduction in ALG1 expression. Although several of his clinical features could be explained by the ALG1 variant specifically or considered as part of the presentation of CDGs in general, there were additional phenotypes that suggested an alternative, or additional, genetic diagnosis. Subsequently, he was found to have biallelic pathogenic GAA repeat expansions in FXN on genome sequencing, leading to a diagnosis of FRDA. Given that FRDA explained all his clinical features, the ALG1 variant may have been a hypomorphic form and/or a biochemical phenotype. Our findings underscore the importance of considering FRDA as a differential diagnosis in cases of complex HSP and demonstrate the utility of unbiased genome sequencing approaches that include detection of trinucleotide repeat expansions for progressive motor disorders., (© 2024 Wiley Periodicals LLC.)