Seven (PARK2, PINK1, DJ-1(PARK7), LRRK2, FBXO7, DNAJC6, DNAJC13) out of the 26 identified genes were already known as causing PD, including familial recessive forms, while three (HTRA2, EIF4G1, SNCAIP) genes were PD candidate genes/at risk factors for which a clear link with the disease is not completely established [5, 6]. Here, HTRA2 is linked to Parkinson disease.