RFX6 and atresia of small intestine: Homozygous mutations in the transcription factor (TF) RFX6 are the cause of the MRS associating neonatal diabetes congenital digestive system defects, including biliary atresia, pancreatic hypoplasia, duodenal and/or jejunal atresia, intestinal malrotation, gallbladder aplasia, and cholestasis.