Cholate-CoA ligase (CCL) and bile acid-CoA: amino acid N-acyltransferase (BAAT) sequentially mediate bile-acid amidation. Defects can cause intrahepatic cholestasis. Distinction has required gene sequencing. We assessed potential clinical utility of immunostaining of liver for CCL and BAAT. Using commercially available antibodies against BAAT and CCL, we immunostained liver from an infant with jaundice, deficiency of amidated bile acids, and transcription-terminating mutation in BAAT. CCL was normally expressed. BAAT expression was not detected. Immunostaining may facilitate diagnosis in bile-acid amidation defects.
Keywords: Amidation; Amino acid N-acyltransferase; Bile acid-CoA; Cholate-CoA ligase; Cholestasis; Conjugation; Electrospray ionisation-mass spectroscopy; Immunohistochemistry; Liver; Neonatal hepatitis; SLC27A5; Transmission electron microscopy.