Using low-dose octreotide with diazoxide-resistant congenital hyperinsulinism resulting from compound heterozygous mutations in the ABCC8 gene.

Abstract

Congenital hyperinsulinism (CHI) is an over-secretion of insulin by pancreatic ß-cells, causing hypoglycemia which can inhibit brain development in infants. CHI is primarily associated with mutations in the ABCC8 or KCNJ11 genes, which encode the SUR1 and KIR 6.2 subunits of the ATP-sensitive potassium (KATP) channel. Here, we report a case of hyperinsulinemic hypoglycemia with ABCC8 gene mutation in a full term, female, Korean infant who developed early onset hypoglycemia but was not subject to either genetic or metabolic workup. This infant was later admitted to the ER because of a hypoglycemic seizure, but her metabolic work up revealed that both her fasting insulin and C-peptide levels were within the normal range. Despite this glucagon stimulation produced positive results and the genetic workup revealed c.[298G>T(;)4252C>T] mutations in the ABCC8 gene. This indicated diazoxide treatment, but following an unsuccessful course of treatment we switched to octreotide which helped stabilize her glucose. Over 5 years of follow-up, the patient treated with a low dose of octreotide has had no hypoglycemic event, and her growth and psychomotor development remained within normal ranges. However, she is severely obese (BMI over 97 %) despite using octreotide. Thus, we report a mild case of CHI with octreotide treatment, wherein the patient has normal insulin and C-peptide levels and normal development, but is severe obese.