Liver transplantation in an infant with cerebrotendinous xanthomatosis, cholestasis, and rapid evolution of liver failure.

Background: Cerebrotendinous xanthomatosis (CTX) is a disorder of bile acid (BA) metabolism due to biallelic mutations in CYP27A1. The deposition of cholesterol and cholestanol in multiple tissues results, manifesting as neurologic disease in adults or older children. Neonatal cholestasis (NC) as a presentation of CTX is rare; it may self‐resolve or persist, evolving to require liver transplantation (LT). Methods: We present in the context of similar reports an instance of CTX manifest as NC and requiring LT. Results: A girl aged 4mo was evaluated for NC with normal serum gamma‐glutamyl transpeptidase activity. An extensive diagnostic work‐up, including liver biopsy, identified no etiology. Rapid progression to end‐stage liver disease required LT aged 5mo. The explanted liver showed hepatocyte loss and micronodular cirrhosis. Bile salt export pump (BSEP), encoded by ABCB11, was not demonstrable immunohistochemically. Both severe ABCB11 disease and NR1H4 disease—NR1H4 encodes farsenoid‐X receptor, necessary for ABCB11 transcription—were considered. However, selected liver disorder panel sequencing and mass‐spectrometry urinary BA profiling identified CTX, with homozygosity for the predictedly pathogenic CYP27A1 variant c.646G > C p.(Ala216Pro). Variation in other genes associated with intrahepatic cholestasis was not detected. Immunohistochemical study of the liver‐biopsy specimen found marked deficiency of CYP27A1 expression; BSEP expression was unremarkable. Aged 2y, the girl is free from neurologic disease. Conclusions: Bile acid synthesis disorders should be routinely included in the NC/"neonatal hepatitis" work‐up. The mutually supportive triple approach of BA profiling, immunohistochemical study, and genetic analysis may optimally address diagnosis in CTX, a treatable disease with widely varying presentation. [ABSTRACT FROM AUTHOR]