The ZNF646.KAT8.BCKDK_rs14235 variant was significantly overrepresented in PD + MetS: 30.3% of MetS patients were homozygous for the risk allele compared to 15.6% of non-MetS patients (recessive model OR 3.06, 95% CI 1.24–7.29; p = 0.012). This evidence concerns the gene ZNF646 and Parkinson disease.