Thus, heterozygous mutations of KCNJ6, affecting the pore-forming domain of the GIRK2 channel, result in the Keppen-Lubinsky syndrome, a genetic disorder characterized by severe developmental delay, microcephaly, and intellectual disability (Basel-Vanagaite et al., 2009; Masotti et al., 2015). Here, KCNJ6 is linked to Global developmental delay.