The PDYN gene contains four exons and is located at chromosome 20p13. Exons 1 and 2 encode the 5′ UTR, exon 3 encodes a signal peptide, and exon 4 encodes the dynorphin peptides. Nine SNPs were described in the coding sequence of which only one synonymous SNP in exon 4 (rs6045819) is not rare. Seven alternative transcripts with different 5′-ends were detected in brain tissue; some have novel initiation sites and some contain new exons (Nikoshkov et al. 2005; Telkov et al. 1998).
