SERUM ALPHA‐FETOPROTEIN LEVELS IN EXTRAHEPATIC BILIARY ATRESIA, IDIOPATHIC NEONATAL HEPATITIS AND ALPHA‐1‐ANTITRYPSIN DEFICIENCY (PiZ)

Abstract. Serum alpha‐fetoprotein levels were measured using a sensitive radioimmunoassay in 77 infants presenting with persistent conjugated hyperbilirubinaemia. A broad range of alpha‐fetoprotein concentrations occurred in both the 23 infants with extrahepatic biliary atresia and the 35 with idiopathic neonatal hepatitis but the 13 with alpha‐1‐antitrypsin deficiency had uniformly low levels. High alpha‐fetoprotein concentrations (above 10 000 μg/I) favoured the diagnosis of neonatal hepatitis especially in the first ten weeks of life, but the overlap between neonatal hepatitis and extrahepatic biliary atresia was large and alpha‐fetoprotein determination cannot be recommended as a reliable method for distinguishing the two conditions. Serial alpha‐fetoprotein values showed no consistent relationship with standard liver function tests and gave no guide to prognosis. There was an association between alpha‐fetoprotein production and needle biopsy evidence of hepatic giant cell transformation. The uniformly low alpha‐fetoprotein levels in alpha‐1‐antitrypsin deficient infants with neonatal hepatitis is a new observation and possible mechanisms for disordered glycoprotein release are discussed.