Project description:BackgroundSpinocerebellar ataxia type 29 (SCA29) is an autosomal dominant, non-progressive cerebellar ataxia characterized by infantile-onset hypotonia, gross motor delay and cognitive impairment. Affected individuals exhibit cerebellar dysfunction and often have cerebellar atrophy on neuroimaging. Recently, missense mutations in ITPR1 were determined to be responsible.ResultsClinical information on 21 individuals from 15 unrelated families with ITPR1 mutations was retrospectively collected using standardized questionnaires, including 11 previously unreported singletons and 2 new patients from a previously reported family. We describe the genetic, clinical and neuroimaging features of these patients to further characterize the clinical features of this rare condition and assess for any genotype-phenotype correlation for this disorder. Our cohort consisted of 9 males and 12 females, with ages ranging from 28 months to 49 years. Disease course was non-progressive with infantile-onset hypotonia and delays in motor and speech development. Gait ataxia was present in all individuals and 10 (48%) were not ambulating independently between the ages of 3-12 years of age. Mild-to-moderate cognitive impairment was present in 17 individuals (85%). Cerebellar atrophy developed after initial symptom presentation in 13 individuals (72%) and was not associated with disease progression or worsening functional impairment. We identified 12 different mutations including 6 novel mutations; 10 mutations were missense (with 4 present in >1 individual), 1 a splice site mutation leading to an in-frame insertion and 1 an in-frame deletion. No specific genotype-phenotype correlations were observed within our cohort.ConclusionsOur findings document significant clinical heterogeneity between individuals with SCA29 in a large cohort of molecularly confirmed cases. Based on the retrospective observed clinical features and disease course, we provide recommendations for management. Further research into the natural history of SCA29 through prospective studies is an important next step in better understanding the condition.
Project description:BackgroundAutosomal recessive spinocerebellar ataxia type 4 (SCAR4) is a type of SCA that is a group of hereditary diseases characterized by gait ataxia. The main clinical features of SCAR4 are progressive cerebellar ataxia, pyramidal signs, neuropathy, and macrosaccadic intrusions. To date, many gene dysfunctions have been reported to be associated with SCAR4.Case summaryHere, we report a novel compound heterozygous mutation, c.3288delA (p.Asp1097ThrfsTer6), in the VPS13D gene in a young female Chinese patient. The patient found something wrong with her legs about 10 years ago and presented with the typical characteristics of SCAR4 when she came to the hospital, including ataxia, neuropathy, and positive pyramidal signs. She was then diagnosed with SCAR4 and went home with symptomatic schemes.ConclusionSCAR4 is a hereditary disease characterized by ataxia, pyramidal signs, neuropathy, and macrosaccadic intrusions. We report a novel compound heterozygous mutation, c.3288delA (p.Asp1097ThrfsTer6), in the VPS13D gene, which enriches the gene mutation spectrum and provides additional information about SCAR4.
Project description:Autosomal dominant variants in ELOVL4 cause spinocerebellar ataxia type 34 (SCA34; ATX-ELOVL4), classically associated with a skin condition known as erythrokeratoderma. Here, we report a large Italian-Maltese-Australian family with spinocerebellar ataxia. Notably, while there were dermatological manifestations (eczema), erythrokeratoderma was not present. Using a next-generation sequencing panel, we identified a previously reported ELOVL4 variant, NM_022726.4: c.698C > T p.(Thr233Met). The variant was initially classified as a variant of uncertain significance; however, through segregation studies, we reclassified the variant as likely pathogenic. We next identified an individual from another family (Algerian-Maltese-Australian) with the same ELOVL4 variant with spinocerebellar ataxia but without dermatological manifestations. We subsequently performed the first dedicated literature review of ELOVL4-associated ataxia to gain further insights into genotype-phenotype relationships. We identified a total of 60 reported cases of SCA34 to date. The majority had gait ataxia (88.3%), limb ataxia (76.7%), dysarthria (63.3%), and nystagmus (58.3%). Of note, skin lesions related to erythrokeratoderma were seen in a minority of cases (33.3%). Other extracerebellar manifestations included pyramidal tract signs, autonomic disturbances, retinitis pigmentosa, and cognitive impairment. For brain MRI data, cerebellar atrophy was seen in all cases (100%), whereas the hot cross bun sign (typically associated with multiple system atrophy type C) was seen in 32.4% of cases. Our family study and literature review highlight the variable phenotypic spectrum of SCA34. Importantly, it shows that erythrokeratoderma is not found in most cases and that, while a dermatological assessment may be helpful in these patients, SCA34 diagnosis should be considered irrespective of dermatological manifestations.
Project description:Genetic mutations in transglutaminase 6 (TGM6) are recently identified to be associated with spinocerebellar ataxia type 35 (SCA35). We report a Hispanic SCA35 patient, who was confirmed to have a heterozygous, single-nucleotide deletion in TGM6, causing a frameshift mutation with a premature stop codon. An immune-mediated ataxia previously found to be associated with autoantibody reactivity to TG6 may share a similar pathomechanism to SCA35, suggesting a converging role for TG6 in cerebellar function.
Project description:Ashton C et al report a retrospective multi-centre cohort of 34 patients from Canada, France, Austria and Australia with spinocerebellar ataxia 27B, describing the common feature of episodic ataxia and other episodic features, as well as the inefficacy of acetazolamide in these patients.
Project description:Elongation of very long chain fatty acids-4 (ELOVL4) is essential for synthesis of very long chain polyunsaturated and saturated fatty acids (VLC-PUFA and VLC-SFA, respectively) of chain length greater than 26 carbons. Mutations in the ELOVL4 gene cause several distinct neurodegenerative diseases including Stargardt-like macular dystrophy (STGD3), spinocerebellar ataxia 34 (SCA34), and a neuro-ichthyotic syndrome with severe seizures and spasticity, as well as erythrokeratitis variabilis (EKV), a skin disorder. However, the relationship between ELOVL4 mutations, its VLC-PUFA and VLC-SFA products, and specific neurological symptoms remains unclear. We generated a knock-in rat line (SCA34-KI) that expresses the 736T>G (p.W246G) form of ELOVL4 that causes human SCA34. Lipids were analyzed by gas chromatography and mass spectrometry. Retinal function was assessed using electroretinography. Retinal integrity was assessed by histology, optical coherence tomography, and immunolabeling. Analysis of retina and skin lipids showed that the W246G mutation selectively impaired synthesis of VLC-SFA, but not VLC-PUFA. Homozygous SCA34-KI rats showed reduced ERG a- and b-wave amplitudes by 90 days of age, particularly for scotopic responses. Anatomical analyses revealed no indication of neurodegeneration in heterozygote or homozygote SCA34-KI rats out to 6-7 months of age. These studies reveal a previously unrecognized role for VLC-SFA in regulating retinal function, particularly transmission from photoreceptors to the inner retina, in the absence of neurodegeneration. Furthermore, these findings suggest that the tissue specificity and symptoms associated with disease-causing ELOVL4 mutations likely arise from selective differences in the ability of the mutant ELOVL4 enzymes to support synthesis of VLC-PUFA and/or VLC-SFA.
Project description:A 58-year-old man consulted our hospital due to a 2-year history of dysarthria and a 1-month history of blepharospasm. In addition to the ataxic dysarthria and blepharospasm, a neurological examination demonstrated slight ataxia of the trunk and lower limbs. Brain MRI demonstrated atrophy of the upper portion of the cerebellar vermis. Gene analysis established a diagnosis of spinocerebellar ataxia type 31 (SCA31). Single photon emission computed tomography (SPECT) with the three-dimensional stereotaxic ROI template (3DSRT) software program demonstrated hyperperfusion in the lenticular nucleus and thalamus. Although the association between SCA31 and blepharospasm in our patient remains unclear, we considered that this combination might be more than coincidental.