PRKN and Parkinson disease: Regarding the latter, PCR amplification of exon 4 of PARK2 failed after several attempts, and subsequent MPLA analysis confirmed a homozygous, pathogenic deletion in exon 4 of the PARK2 gene (p.Ala138Glyfs*7), leading to a diagnosis of EO-PD, with both parents subsequently identified as being carriers of the same mutation (Figure 1).