PRKN and Parkinson disease: During the following years three important genes coding for autosomal recessive PD were found, one for parkin, PRKN, the most common gene for young onset parkinsonism, and PINK1 and DJ-1 as autosomal recessive causes of PD (Kitada et al., 1998; Valente et al., 2001; Bonifati et al., 2003).