Diagnosis of MODY in the offspring of parents with insulin-dependent and non-insulin-dependent diabetes mellitus

Maturity Onset Diabetes of the Young (MODY) is an autosomal dominant monoge nic form of type 2 diabetes mellitus (DM) representing 5% of youth-onset DM in the Caucasian population. In young adults the disease can be present as either non-insulin dependent or insulin-dependent DM. The diagnosis of thi s genetic disorder in children and adolescents is rare because of the mild glucose metabolism disorder at this time. We performed a metabolic, autoimm une and genetic study in 40 offspring of young parents affected by insulin- dependent DM (Croup A) and in 35 offspring of young parents affected by ear ly-onset non-insulin-dependent DM (Group B), Two children of Group A (5%) w ere found to be affected by fasting hyperglycemia and carry a GCK gene muta tion that in one case was present also in the diabetic father. Eighteen off spring of Group B (51%) were positive for GCK or BNF-1 alpha gene mutations present in the affected parents. All but two of these young patients had i mpaired fasting glucose (IFG) or impaired glucose tolerance (IGT), Eleven o f them were younger than 16 years. We conclude that screening for DM in you th should be extended to MODY in young families with both non-insulin-depen dent and insulin-dependent DM, The sensitivity of the metabolic tests will precede the genetic diagnosis.