Background: Maturity onset diabetes of the young (MODY) is the most
commonly reported form of monogenic diabetes in the pediatric
population. Only a few cases of digenic MODY have been reported up to
now. Case report: A female patient was diagnosed with diabetes at the
age of 7 years and was treated with insulin. A strong family history of
diabetes was present in the maternal side of the family. The patient
also presented hypomagnesemia, glomerulocystic kidney disease and a
bicornuate uterus. Genetic testing of the patient revealed that she was
a double heterozygous carrier of HNF1A gene variant c.685C > T;
(p.Arg229Ter) and a whole gene deletion of the HNF1B gene. Her mother
was a carrier of the same HNF1A variant. Conclusion: Digenic inheritance
of MODY pathogenic variants is probably more common than currently
reported in literature. The use of Next Generation Sequencing panels in
testing strategies for MODY could unmask such cases that would otherwise
remain undiagnosed