Spinocerebellar ataxia type 17:: Report of a family with reduced penetrance of an unstable GIn49 TBP allele, haplotype analysis supporting a founder effect for unstable alleles and comparative analysis of SCA17 genotypes -: art. no. 27

Background: Spinocerebellar ataxia type 17 ( SCA17), a neurodegenerative disorder in man, is caused by an expanded polymorphic polyglutamine-encoding trinucleotide repeat in the gene for TATA- box binding protein (TBP), a main transcription factor. Observed pathogenic expansions ranged from 43 - 63 glutamine (Gln) codons (Gln(43-63)). Reduced penetrance is known for Gln(43-48) alleles. In the vast majority of families with SCA17 an expanded CAG repeat interrupted by a CAA CAG CAA element is inherited stably.