We studied two patients with complex mutations in the ABCC8 gene with CHI and used in vitro studies to explore the potential disease mechanism and the contribution of the various mutant allelles.
A genetic analysis of the SUR1 gene using peripheral white blood cells is considered a useful parameter to determine the optimal surgical strategy for the treatment of PHHI.
Recent advances in genetics have linked CHI to mutations in 9 genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A and HNF1A).
A 16-year-old female with CHI due to a dominant ABCC8 gene mutation was switched from diazoxide therapy to sirolimus, due to the hypertrichosis side effect of diazoxide.
Congenital hyperinsulinism in infancy (CHI) is characterized by unregulated insulin secretion from pancreatic β-cells; severe forms are associated with defects in ABCC8 and KCNJ11 genes encoding sulfonylurea receptor 1 (SUR1) and Kir6.2 subunits, which form ATP-sensitive K(+) (K(ATP)) channels in β-cells.
PHHI is caused by mutations in SUR1, which is a member of the ATP-binding cassette superfamily, and in Kir6.2, which is a member of the inwardly rectifying family of potassium channels.
Germ-line, paternally inherited, mutations of the SUR1 or KIR6.2 genes, together with somatic maternal haplo-insufficiency for 11p15.5, were shown to result in focal CHI.
Recessive mutations of sulfonylurea receptor 1 (SUR1) and potassium inward rectifier 6.2 (Kir6.2), the two adjacent genes on chromosome 11p that comprise the beta-cell plasma membrane ATP-sensitive K(+) (K(ATP)) channels, are responsible for the most common form of congenital hyperinsulinism in children.