The term “congenital hyperinsulinism” (=CHI) covers various disorders that result in uncontrolled, recurring, excessive insulin secretion. Insulin release in healthy individuals is governed by prevailing blood sugar (=glucose) levels. When blood glucose is low (=hypoglycemia), insulin release from ᵦ-cells in the pancreas is turned off. In hypoglycemia, another pancreatic hormone, glucagon, the adrenal hormones cortisol and adrenalin, as well as growth hormones are released and liberate glucose from reserves stored in the body. Glucose is an important energy source for the brain, but nearly all tissues can use it. Insulin builds up the liver’s store of glucose (=glycogen) and at the same time prevents glucose release. Additional important energy sources are fatty acids, triglycerides, ketone bodies (acetone, beta-hydrobutyric acid, acetoacetic acid) and amino acids (= protein building blocks).
A number of very different illnesses can lead to hypoglycemia. Besides hyperinsulinism, these include disruptions in the breakdown of fatty acids and amino acids, in energy reserve storage or hormones that cause a rise in blood glucose.
Congenital hyperinsulinism therefore is an umbrella term for:
A variety of genetic defects stemming from differing hereditary patterns may be underlying causes.