Variable Phenotype of Diabetes Mellitus in Siblings with a Homozygous PTF1A Enhancer Mutation

Neonatal diabetes is a rare form of diabetes, characterized by onset in the first 6 months of life. A number of cases are due to pancreas agenesis. Recently, PTF1A enhancer mutations have been shown to cause neonatal diabetes associated with pancreatic agenesis. Herein, we report the clinical features of two siblings with PTF1A enhancer mutations, one of whom had neonatal diabetes, whereas the elder sister had a milder form of the disease with onset of diabetes at 9 years of age.