[Permanent neonatal diabetes and recessive mutation in the INS gene: a familial history]

Permanent neonatal diabetes mellitus is a rare disorder usually presenting within the first few weeks or months of life and defined by chronic hyperglycemia due to severe nonautoimmune insulin deficiency. Nonsyndromic neonatal diabetes is genetically heterogeneous and several genes have been linked to this disorder. Here, we report on a new homozygous recessive mutation in the INS gene in 2 siblings born to consanguineous parents and diagnosed with permanent neonatal diabetes without extrapancreatic features. Their clinically unaffected parents were heterozygous. Their phenotype was also characterized by severe intrauterine growth retardation, most likely reflecting severe insulin deficiency in prenatal life, hyperglycemia, and moderate dehydration in the first few days of life. Their clinical course was uneventful after introduction of insulin therapy with catch-up growth and acquisition of normal developmental milestones.