Crigler Najjar Syndrome Type 2 (CNS Type 2): An Unwonted Cause of Jaundice in Adults.

Crigler Najjar Syndrome (CNS) Type 2 is an uncommon genetic disorder characterised by non-haemolytic unconjugated hyperbilirubinemia. It is caused by mutations in the UGT1A1 gene which codes for the enzyme uridine diphosphate glucoronosyl transferase- 1, required for the conjugation and further excretion of bilirubin from the body. Affected individuals are usually asymptomatic apart from the jaundice and investigations reveal isolated indirect hyperbilirubinemia. It can be conveniently diagnosed by evaluating the response to phenobarbitone in terms of fall in bilirubin levels. Genetic testing of the UGT1A1 gene for mutations is the diagnostic clincher. However, case reports documenting the genetic mutational analysis are sparse. We report one such rare case.