A term neonate has had unconjugated jaundice since day 3 of life. There is no evidence of haemolysis. Total serum bilirubin fluctuates between 16 and 24 mg/dL. Administration of phenobarbital produces a clear fall in bilirubin levels. His father was treated with phenobarbital for similar jaundice in infancy. What is the MOST likely diagnosis?
- A Crigler-Najjar syndrome type I
- B Gilbert syndrome
- C Crigler-Najjar syndrome type II (Arias syndrome) ✓
- D Lucey-Driscoll syndrome
Explanation
Crigler-Najjar type II results from a partial defect of UDP-glucuronosyltransferase, causing unconjugated jaundice from the neonatal period with bilirubin usually between 15 and 25 mg/dL. It characteristically responds to phenobarbital, which induces residual enzyme activity, and it shows familial occurrence consistent with its autosomal dominant or recessive inheritance. Type I has a complete enzyme defect, bilirubin exceeding 25 mg/dL, and no response to phenobarbital. Gilbert is milder and typically presents after childhood, while Lucey-Driscoll is transient neonatal jaundice from a maternal serum inhibitor.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.