The clinical features and genetic diagnosis in a large olivopontocerebellar atrophy type 1 family

Abstract

Objective To make clinical and genetic diagnosis of members within a family with an autosomal dominant olivopontocerebellar atrophy, and to analyze the relationship between clinical features and genotype. Methods Pedigree analysis, the neurological examination, accessory test like brain MRI, and the molecular genetic analysis of the coding region of SCA1(spinocerebellar ataxia type 1)、SCA3 、SCA7 、SCA12 and DRPLA(dentatorubral and palliodoluysian atrophy). Results The family manifested an autosomal dominant inheritance. In the two typical patients, brain MRI showed remarkable atrophy on cerebellum、brain stem and pons varolii. The CAG lengths of SCA3 、SCA7、SCA12 and DRPLA were normal in all family members. CAG repeat sizes of SCA1 ranged from 29 to 37 repeats in 10 healthy controls and 4 unaffected family members, whereas in the two patients, Ⅳ3 and Ⅳ7, the mutated allele were 53 and 67 respectively. The daughter of Ⅳ3 was diagnosed as presymptomatic SCA1 patient, due to the fact that she carries the mutated allele 57. Conclusion This family was genetically and clinically diagnosed to be autosomal dominant SCA1. The clinical features of SCA1 are heterogeneous, so genetic diagnosis is very important. Key words: Spinocerebellar ataxia; Olivopontocerebellar atrophy; Dynamic mutation; Family; Genetic diagnosis