Congenital Hyperinsulinism: Report of a New Mutation

Congenital hyperinsulinism is a rare condition characterized by inappropriate secretion of insulin leading to recurrent and persistent hypoglycaemia, which may subsequently lead to permanent brain damage. Genetic mutations have been identified in approximately 50% of cases attributable to defects in at least 11 genes. The clinical presentation is nonspecific. Seizures during infancy or pallor, diaphoresis and tachycardia, in childhood, can be the first presentation.Medical treatment includes diazoxide, chlorthiazide, nifedipine and octreotide. In diazoxide unresponsive patients, further investigations including genetic studies and 18F-DOP PET scan may be warranted to identify the two distinct types of congenital hyperinsulinism described in the literature: focal and diffuse forms. Focal hyperinsulinism may be cured by excision of the focal lesion; whereas, diffuse hyperinsulinism may require near-total pancreatectomy. We report a female newborn with focal hyperinsulinism but with multifocal lesions. This is rarely described in the current literature. The genetic mutation identified in our case was ABCC8c.1792C>Tp.Arg598* of paternal origin, a new mutation, not previously described in the literature. Due to the multifocal nature of this form of hyperinsulinism, the patient developed recurrent episodes of hypoglycaemia despite excision of the focal lesion. Further genetic studies may be necessary in the identification of possible genetic mutations associated with multifocal hyperinsulinism, which may aid the management and predict the prognosis.