Mutations in the RFX6 gene were recently described to underlie a distinct autosomal recessive syndrome of neonatal diabetes comprising intestinal atresia and hepatobiliary abnormalities. Until now, only six patients harboring RFX6 mutations have been reported. We report on a new case due to a novel homozygous splice site mutation and update on the clinical outcome of a previously reported patient. In addition we review the clinical and molecular features of all RFX6 mutated cases to better characterize the syndrome. Our results suggest that despite the early postnatal fulminant course, patients who survive may expect a relatively favorable prognosis. © 2011 Wiley Periodicals, Inc.