BACKGROUND: The etiology of mild hyperglycemia without ketoacidosis in young children is often unknown. Maturity onset diabetes of youth (MODY) is a form of diabetes mellitus (DM) characterized by fasting hyperglycemia without evidence for autoimmune destruction of beta-cells. METHODS: We genetically analyzed four families of young children with fasting hyperglycemia with family histories of diabetes for mutations in the genes for hepatocyte nuclear factor 4 alpha (HNF4alpha), glucokinase (GCK), and hepatocyte nuclear factor 1 alpha (HNF1alpha), the genes responsible for MODY1, MODY2, and MODY3, respectively. RESULTS: We identified mutations in GCK (Gly258Asp, Arg303Trp, and Arg191Gln) in three of the four families. Molecular genetic characterization in these children clarified the etiology and prognosis of the hyperglycemia and allowed discontinuation of insulin therapy in one family. CONCLUSIONS: We conclude that molecular evaluation for MODY in children with mild fasting hyperglycemia without ketosis with family histories of diabetes can provide important prognostic information to guide therapy and exclude preclinical type 1 diabetes mellitus.
BACKGROUND: The etiology of mild hyperglycemia without ketoacidosis in young children is often unknown. Maturity onset diabetes of youth (MODY) is a form of diabetes mellitus (DM) characterized by fasting hyperglycemia without evidence for autoimmune destruction of beta-cells. METHODS: We genetically analyzed four families of young children with fasting hyperglycemia with family histories of diabetes for mutations in the genes for hepatocyte nuclear factor 4 alpha (HNF4alpha), glucokinase (GCK), and hepatocyte nuclear factor 1 alpha (HNF1alpha), the genes responsible for MODY1, MODY2, and MODY3, respectively. RESULTS: We identified mutations in GCK (Gly258Asp, Arg303Trp, and Arg191Gln) in three of the four families. Molecular genetic characterization in these children clarified the etiology and prognosis of the hyperglycemia and allowed discontinuation of insulin therapy in one family. CONCLUSIONS: We conclude that molecular evaluation for MODY in children with mild fasting hyperglycemia without ketosis with family histories of diabetes can provide important prognostic information to guide therapy and exclude preclinical type 1 diabetes mellitus.