Hypoglycemia as a result of hyperinsulinism in the newborn (HI) is a clinic
ally heterogeneous entity that presents a diagnostic and therapeutic challe
nge to the treating physician. Recent discoveries have shown that mutations
in four different beta-cell genes cause HI. However, for many HI patients,
the molecular etiology is unknown, and other genes might be involved. The
study of the molecular biology of HI has Zed to a better understanding of p
ancreatic beta-cell physiology. In the future, this might result in the dev
elopment of novel drugs for the treatment of both hyperinsulinism and non-i
nsulin-dependent diabetes.