RFX6 and diabetes mellitus: In two previously reported families of neonatal diabetes children with homozygous p.Arg181Gln RFX615, 18 or RFX6 p.His293Leufs19, the genetic information available on RFX6 heterozygous family members was also suggestive of reduced penetrance of diabetes (Supplementary Figs 2 and 3).