Another intriguing example is the association between a relatively common CNV (frequency = 0.22%) affecting exon 2 and intron 2–3 of PRKN [MIM: 602544]—a gene causing juvenile autosomal recessive Parkinson’s disease [MIM: 600116]—and sleep disorders such as insomnia and hypersomnia. This evidence concerns the gene PRKN and hypersomnia.