PMS2 and Huntington disease: The latest HD genetic modifier GWAS with more than 9,000 HD patients found an association with a cis-eQTL for increased MSH3 expression in blood cells and identified additional loci with candidate modifier genes involved in DNA maintenance processes, PMS1 (post-meiotic segregation increased 1 homolog), PMS2 (post-meiotic segregation increased 2 homolog) and LIG1 (DNA Ligase 1) [23].