Extrahepatic biliary atresia and normal‐range serum gamma‐glutamyltranspeptidase activity: A case report

An infant with biliary atresia had normal-range ('low') serum gamma-glutamyltranspeptidase (GGT) activity, exceptional because GGT generally is elevated in biliary atresia. Mechanisms underlying low-GGT cholestasis in biliary atresia are not defined, but the phenomenon is associated with worse clinical outcome. Testing in our patient revealed no variants in genes mutated in several disorders also associated with poor prognosis and with low-GGT cholestasis; indeed, at age 14 months she has stable disease with unremarkable biomarker values. Nonetheless, we recommend extended investigations in such patients, including genetic testing, to detect coexistent disorders and to expand understanding of GGT in biliary atresia.