Although none of the KCNJ6 SNPs studied here are coding SNPs, recent studies have shown that it is not only the coding SNPs that change the protein that influence a trait, but non-coding intronic and synonymous exonic SNPs can affect gene function. While synonymous SNPs (sSNPs), although in the coding region, do not change the protein sequence encoded by the gene, they can contribute to variation in effects in at least two ways: sSNPs could affect mRNA stability and thus protein expression and enzymatic activity and sSNPs can affect protein conformation which have functional and clinical consequences (Hunt et al., 2009; Sauna and Kimchi-Sarfaty, 2011). Intronic SNPs have effects on splicing and gene expression, both of which have functional and clinical consequences (Cooper, 2010; Harrison, 2015; Jo and Choi, 2015).
