PDYN and alcohol dependence: Interestingly, another study identified a variant associated with alcohol dependence that introduces a CpG site in PDYN. Even though carriers of the T risk allele had the highest binding affinity for a protein that regulates PDYN expression positively the researchers found that increased DNA methylation of the non-risk C allele increased its binding affinity for this protein more than the non-methylated C allele but still less than the risk T allele.