KCNJ2 and Andersen-Tawil syndrome: Carriers of loss-of-function Kir2.1 mutations (Andersen-Tawil syndrome) typically exhibit morphological abnormalities including short stature, facial abnormalities, and unusual bone structure in their extremities (Plaster et al., 2001; Tristani-Firouzi and Etheridge, 2010).