Mondo Description Crigler-Najjar syndrome type 1 (CNS1) is the most severe form of CNS, a hereditary disorder of hepatic bilirubin conjugation, characterized by severe neonatal unconjugated hyperbilirubinemia due to a complete absence of hepatic bilirubin glucuronosyltransferase (BGT).

Uniprot Description Patients have severe hyperbilirubinemia and usually die of kernicterus (bilirubin accumulation in the basal ganglia and brainstem nuclei) within the first year of life. CN1 inheritance is autosomal recessive.