PRKN and Parkinson disease: However, other studies have shown that heterozygous mutations in this gene might be a risk factor for the development of PD (Huttenlocher et al., 2015).The novel compound heterozygous mutations in PARK2 reported in this study included a gross deletion of exons 1 to 2 (EX 1‐2 del) and a splicing mutation (c.619‐, G > C), without any other known PD‐related mutation.