Some genes are linked to the atypical recessive forms of PD (ATP13A2-PARK9, PLA2G6-PARK14, and FBXO7-PARK15) or X-linked (ATP6A2 and TAF1), whereas others (PARK3, UCHL1, PARK10, GIGYF2, PARK12, HTRA2, PARK16, EIF4G1, DNAJ, HLA-DR, GAK-DGKQ, SYNJ1, and GBAP1) may influence PD susceptibility [57]. This evidence concerns the gene HTRA2 and Parkinson disease.