ATN1 and Huntington disease: In the present study we analyzed 4 polymorphisms that have not yet been described in modulation of AO in HD: CAG repeat of the DRPLA gene (OMIM no. 125370), CTG repeat of the DMPK (OMIM no. 160900), CAG repeat of the ATXN1 (OMIM no. 164400) gene, and CTG repeat of the JPH3 (OMIM no. 606438) implicated in Huntington's disease-like-2 (HDL2), a phenocopy of Huntington's disease.