Comprehensive phenotype of the p.Arg420his allelic form of spinocerebellar ataxia type 13.

The p.Arg420His allelic form of spinocerebellar ataxia type 13 has been reported in a large Filipino kindred, as well as three European index cases, one with an affected offspring. Haplotype analysis has confirmed independent mutational events. All individuals share adult-onset, predominantly cerebellar signs and a slowly progressive course. However, a comprehensive phenotypic description has yet to be published on SCA13(p.Arg420His). In this study, we present the results of a detailed neurological clinical and diagnostic testing on 21 mutation-positive members of a four-generation Filipino family to further define this disease, aiding diagnosis and prognosis.