Imprinting is a phenomenon in which epigenetic modifications lead to expression or suppression of alleles of some genes based on their parental origin. Wilms tumor-2 (WT2; MIM 194071) is defined by maternal-specific loss of heterozygosity of a critical region on chromosome 11p15.5 that includes several imprinted genes. KCNQ1DN is an imprinted gene located within the WT2 critical region that is expressed from the maternal allele (Xin et al., 2000 [PubMed 11056398]).[supplied by OMIM, Mar 2008].