A novel homozygous mutation in the mannose phosphate isomerase gene causing congenital disorder of glycation and hyperinsulinemic hypoglycemia in an infant

Key Clinical Message We report a 4 years girl with congenital disorders of glycosylation (CDG) type Ib due to a novel homozygous mutation in MPI gene. She presented with diazoxide-responsive hyperinsulinemic hypoglycemia. CDG should be considered in unexplained hypoglycemia particularly in consanguineous families. Diagnosis enables monitoring/prevention of disease comorbidities and early effective treatment.