The KCNJ11 c.685G > A, p.Glu229Lys (Family 315) is indeed very interesting as the father of the index patient carries the mutation, too, and his diabetes was diagnosed at the age of 40 years while the diabetes of the index patient was diagnosed at the age of 13, suggesting a variable expressivity of the alteration, probably affected by other genetic and/or environmental factors. The gene discussed is KCNJ11; the disease is diabetes mellitus.