IGF2 and male infertility: Indeed, the improper methylation of the paternally imprinted potassium voltage-gated channel subfamily Q member 1 (KCNQ1) gene, insulin-like growth factor 2 (IGF-2) gene and KCNQ1 overlapping transcript 1 (KCNQ1OT1) genes have been found to be associated with oligozoospermia and asthenospermia in infertile males [22].