Transient neonatal diabetes due to a disease causing novel variant in the ATP-binding cassette subfamily C member 8 () gene unmasks maturity-onset diabetes of the young (MODY) diabetes cases within a family.

Objectives: Neonatal diabetes mellitus (NDM) is a rare monogenic diabetes form, occurring mainly from ATP-binding cassette subfamily C member 8 () and mutations. mutations have also been found to cause adult-onset diabetes. What is new?: •Novel mutation in an NDM case •Heterogeneous clinical presentation of diabetes and response to sulfonylurea therapy among family members with the same mutation.