title: A comprehensive clinical and genetic study of a large Mexican population with spinocerebellar ataxia type 7.
abstract: Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disorder characterized by progressive cerebellar ataxia associated with macular degeneration. We recently described one of the largest series of patients with SCA7 that originated from a founder effect in a Mexican population, which allowed us to perform herein the first comprehensive clinical, neurophysiological, and genetic characterization of Mexican patients with SCA7. In this study, 50 patients, categorized into adult or early phenotype, were clinically assessed using standard neurological exams and genotyped using fluorescent PCR and capillary electrophoresis. Patients with SCA7 exhibited the classical phenotype of the disease characterized by cerebellar ataxia and visual loss; however, we reported, for the first time, frontal-executive disorders and altered sensory-motor peripheral neuropathy in these patients. Semiquantitative analysis of ataxia-associated symptoms was performed using Scale for the Assessment and Rating of Ataxia (SARA) and the Brief Ataxia Rating Scale (BARS) scores, while extracerebellar features were measured employing the Inventory of Non-ataxia Symptoms (INAS) scale. Ataxia rating scales confirmed the critical role size of cytosine-adenine-guanine (CAG) repeat size on age at onset and disease severity, while analysis of CAG repeat instability showed that paternal rather than maternal transmission led to greater instability.
authors.affiliation: Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico.
authors.forename: L
authors.initials: L
authors.lastname: Velázquez-Pérez
authors.forename: C M
authors.initials: CM
authors.lastname: Cerecedo-Zapata
authors.forename: O
authors.initials: O
authors.lastname: Hernández-Hernández
authors.forename: E
authors.initials: E
authors.lastname: Martínez-Cruz
authors.forename: Y S
authors.initials: YS
authors.lastname: Tapia-Guerrero
authors.forename: R
authors.initials: R
authors.lastname: González-Piña
authors.forename: J
authors.initials: J
authors.lastname: Salas-Vargas
authors.forename: R
authors.initials: R
authors.lastname: Rodríguez-Labrada
authors.forename: R
authors.initials: R
authors.lastname: Gurrola-Betancourth
authors.forename: N
authors.initials: N
authors.lastname: Leyva-García
authors.forename: B
authors.initials: B
authors.lastname: Cisneros
authors.forename: J J
authors.initials: JJ
authors.lastname: Magaña
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology / Q000523:psychology; D055815:Young Adult