Mitochondrial haplogroups demonstrated a significantly protective effect for PD risk only in females [3]; GAPDH gene variants are associated with an increased PD risk in men [82], while small CGG expansion (41–54 repeats) in the fragile X mental retardation 1 (FMR1) gene, called FMR1 “gray zone” alleles (GZ), are a significant risk factor for parkinsonism, more prominent in men [83]. Here, GAPDH is linked to Parkinson disease.