Bile acid profiles in neonatal intrahepatic cholestasis caused by citrin deficiency

Background Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is characterized by conjugated hyperbilirubinemia and increased plasma bile acid concentrations. However, the underlying mechanisms remain unclear. We established a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneously quantifying plasma bile acids and examined bile acid profiles in NICCD infants. Methods We measured 15 bile acids within 15 min and found a wide linear range for individual bile acids. Results The within-run and run-to-run CV of all bile acids was 1.2–10.9% and 3.1–10.8%, respectively, with a mean recovery of 90.5–112.6%. Compared to infants with citrullinemia without mutations in SLC25A13 (non-NICCD), NICCD infants showed increased plasma total bile acid concentrations (mean: 201 vs. 42 μM, p < 0.001), with a distinct bile acid profile characterized by increased conjugated primary bile acid concentrations. The calculated ratios, including primary/secondary bile acid (714 vs. 235, p < 0.05) and conjugated/free bile acid (371 vs. 125, p < 0.05) ratios, were higher in NICCD infants. The area under receiver operating characteristic curve for conjugated/free bile acid ratio to identify infants with NICCD was 0.871 (95% confidence interval, 0.713–1.0). Conclusions Together, our findings indicated plasma bile acid profile as a potential noninvasive diagnostic biomarker for NICCD.