BackgroundInfants with Alagille syndrome (ALGS) need to be promptly differentiated from biliary atresia (BA) at an early stage. ALGS is an autosomal, dominant, multisystem disorder with variable phenotypic penetrance caused by heterozygous mutations in JAG1 or NOTCH2, which encode the Notch signaling pathway.Case presentationWe report two cases, both with cholestatic jaundice as the main manifestation, in which BA was excluded and finally diagnosed as ALGS based on characteristic facial features, serological tests, imaging, laparoscopic cholangiography, pathology and genetic findings. Both cases are novel mutant genes on chromosome 20 that have not been reported in the literature. The mutation in patient 1 was a novel heterozygous nonsense mutation (NM_000214 exon20, c.2419G > T, p.E807Ter), which was a spontaneous mutation. Followed up to 1 year and 6 months, the symptoms resolved with ursodeoxycholic acid and cholestyramine, and the jaundice has now subsided. Patient 2 was a novel heterozygous frameshift mutation (NM_000214 exon19, c.2367–2368dupTC, p.P790Lfs*31), which was inherited from his mother. This patient was followed up to 9 months and is currently awaiting liver transplantation.ConclusionBoth cholestatic infants reported combined to exclude BA, avoid Kasai portoenterostomy (KPE), and definitively diagnose ALGS. Broadening the spectrum of JAG1 gene mutations.

Meconium peritonitis (MP) combined with intestinal atresia (IA) is a rare neonatal condition, and it is even rarer in combination with biliary atresia (BA). We describe a case of an infant who developed short bowel syndrome after partial intestinal resection due to MP and IA, along with a Santullienterostomy. During continuous enteral and parenteral nutrition, the stool color became paler. BA was identified by elevated direct bilirubin (DBIL), gamma-glutamyltransferase (GGT), serum matrix metalloproteinase-7 (MMP-7), and hepatobiliary ultrasound; then, Kasai portoenterostomy (KPE) was performed promptly. The Roux-en-Y limb was adjusted intraoperatively to preserve the maximum length of the small intestine while closing the enterostomy. After the operation, the infant gradually adapted to enteral nutrition, his bilirubin level returned to normal, and his weight gradually caught up to the normal range. Although rare, BA should be suspected when MP is combined with IA and when the stool becomes paler in color in the enterostomy state.