Congenital hyperinsulinism due to HNF4A deficiency

Congenital hyperinsulinism due to HNF4A deficiency (also known as HNF4A-related hyperinsulinism or MODY1-associated neonatal hyperinsulinism) is a rare genetic disorder caused by mutations in the HNF4A gene, which encodes hepatocyte nuclear factor 4-alpha, a transcription factor important in pancreatic beta-cell function and liver metabolism. This condition is characterized by excessive insulin secretion from the pancreatic beta cells, leading to persistent hypoglycemia (low blood sugar) that typically presents in the neonatal or early infancy period. Affected newborns are often macrosomic (large for gestational age) and may present with severe hypoglycemia requiring urgent treatment. The condition primarily affects the endocrine system, specifically the insulin-secreting beta cells of the pancreas. Key symptoms include recurrent episodes of hypoglycemia, which can manifest as seizures, lethargy, poor feeding, jitteriness, and if untreated, can lead to permanent neurological damage. Some patients may also have mildly elevated liver transaminases or other hepatic features. Notably, individuals with HNF4A mutations may transition from hyperinsulinism in infancy to maturity-onset diabetes of the young type 1 (MODY1) later in life, typically in adolescence or early adulthood, reflecting the dual role of HNF4A in beta-cell function across the lifespan. Treatment of the hyperinsulinism phase focuses on maintaining normal blood glucose levels. Diazoxide, which suppresses insulin secretion, is generally effective in most patients with HNF4A-related hyperinsulinism, distinguishing it from some other forms of congenital hyperinsulinism that are diazoxide-unresponsive. Frequent feeding and intravenous glucose may be required in the acute neonatal period. Long-term monitoring is essential, as affected individuals need surveillance for the eventual development of diabetes mellitus. Genetic counseling is important given the autosomal dominant inheritance pattern, and family members should be screened for both hyperinsulinism and diabetes.

Common questions about Congenital hyperinsulinism due to HNF4A deficiency