Early-onset phenotype in a patient with an intermediate allele and a large SCA1 expansion: a case report.

BACKGROUND: Spinocerebellar ataxia type 1, is a rare neurodegenerative disorder with autosomal dominant inheritance belonging to the polyglutamine diseases. The diagnosis of this disease requires genetic testing that may also include the search for CAT interruption of the CAG repeat tract. CASE PRESENTATION: One 23-years-old patient suffers from a severe ataxia, with early-onset and rapid progression of the disease. His father might have been affected, but no molecular confirmation has been performed. The genetic results were negative for the Friedreich's ataxia, spinocerebellar ataxia type 2, 3, 6, 7 and 17. The numbers of CAG repeats in the ATXN1 gene was assessed by fluorescent PCR, tripled-primed PCR and enzymatic digestion for the search of sequence interruption in the CAG repeats. The patient carried one pathogenic allele of 61 CAG and one intermediate allele of 37 CAG in the ATXN1 gene. Both alleles were uninterrupted. CONCLUSIONS: We report a rare case of spinocerebellar ataxia type 1 with an intermediate allele and a large SCA1 expansion. The determination of the absence of CAT interruption brought crucial information concerning this molecular diagnosis, the prediction of the disease and had practical consequences for genetic counseling.

Late-onset Kjellin syndrome: Diagnosis of SPG11 on fundus examination.

INTRODUCTION: Spastic paraplegia (SPG) is a heterogenous group of neurodegenerative disorders, that may include ocular involvement. Here we report the clinical data of a patient with late-onset Kjellin syndrome, a peculiar form of hereditary SPG with macular dystrophy. MATERIALS AND METHODS: Clinical, functional and multimodal retinal imaging data were collected. Genetic testing was performed by Whole Exome Sequencing (WES). RESULTS: A 52-year-old female patient with SPG of unknown origin was referred for a progressive visual acuity loss. Multimodal fundus imaging revealed a peculiar macular dystrophy. Given the specific association of macular dystrophy and SPG, a Kjellin syndrome was suspected and genetic testing performed. WES revealed biallelic pathogenic variants in SPG11, co-segregating with disease in the family. CONCLUSION: Careful ophthalmological examination prompted the diagnosis and guided molecular testing. This case underlines the importance of a neuro-ophthalmologic assessment in patients with SPG.

Cognitive Impairment Is Part of the Phenotype of Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS).

BACKGROUND: Little is known about the impact of the cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) on cognition. OBJECTIVE: Our objective was to determine the frequency and severity of cognitive impairment in RFC1-positive patients and describe the pattern of deficits. METHODS: Participants underwent a comprehensive neuropsychological assessment. Volume of the cerebellum and its lobules was measured in those who underwent a 3 Tesla-magnetic resonance scan. RESULTS: Twenty-one patients underwent a complete assessment, including 71% scoring lower than the cutoff at the Montreal Cognitive assessment and 71% having a definite cerebellar cognitive affective/Schmahmann syndrome. Three patients had dementia and seven met the criteria of mild cognitive impairment. Severity of cognitive impairment did not correlate with severity of clinical manifestations. Performance at memory and visuospatial functions tests negatively correlated with the severity of cerebellar manifestations. CONCLUSION: Cognitive manifestations are frequent in RFC1-related disorders. They should be included in the phenotype and screened systematically. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.