Mutant variants in the sodium channel beta-1b subunit (SCN1Bβ), namely S248R and R250T, detected in ERS patients, were found to increase Ito when co-expressed with KCND3, respectively, by 27.44% and 199.89%, compared to wild-type. The gene discussed is KCND3; the disease is amelogenesis imperfecta type 1G.