Should spinocerebellar ataxias be included in the differential diagnosis for Huntington's diseases-like syndromes?

Abstract

In this article, we describe three patients with different spinocerebellar ataxia (SCA) subtypes presenting with unusual movement disorders predominantly characterized by choreoathetosis, which, together with their autosomal dominant pattern of inheritance, resembled the Huntington-like syndromes. From a large SCA cohort, we have observed chorea in 1/35 SCA2, 1/112 SCA3/MJD, and 1/30 SCA7 patients. Twenty-eight patients with SCA1, 11 patients with SCA6, and 3 patients with SCA10 were also evaluated, and none of them presented chorea. We provide a brief report of the three cases, with a video demonstrating chorea. Although a debate regarding the frequency of chorea in SCA patients is a fact, its occurrence, together with the autosomal dominant pattern of inheritance, clearly imposes SCA in the differentials of Huntington-like syndromes. There is some debate about what to include in a list of Huntington-like disorders, with several review articles about Huntington-like syndromes not including SCA in the differential diagnosis, except for SCA17. We believe that SCAs—at least SCA1, SCA2, SCA3/MJD, SCA7 and DRPLA—should be thought in the diagnostic workout of at least the atypical cases, such as those presented in this report.