# Case Report: A rare case of familial progressive cholestasis type 10 in an adult with heterozygous MYO5B variant

## TL;DR

A 36-year-old man with rare familial cholestasis due to a MYO5B gene variant showed symptoms typically seen in children, highlighting the need for genetic testing in adults with unexplained liver issues.

## Contribution

This case report presents a rare adult-onset MYO5B-related progressive familial intrahepatic cholestasis (PFIC) and emphasizes the importance of genetic testing in adults with unexplained liver disease.

## Key findings

- A 36-year-old male with PFIC type 10 presented with delayed-onset symptoms and compound heterozygous MYO5B variants.
- Liver biopsy showed hydropic degeneration and bile thrombi, with no improvement from standard therapies until traditional Chinese medicine was added.
- The case underscores the need to consider MYO5B mutations in adults with hyperbilirubinemia and normal/mildly elevated GGT levels.

## Abstract

Progressive familial intrahepatic cholestasis (PFIC) is a group of rare autosomal recessive cholestatic liver diseases that typically manifest in infancy or childhood. It is characterized by intrahepatic cholestasis, jaundice, pruritus, and malabsorption, with potential progression to cirrhosis, liver failure, and hepatocellular carcinoma. Here, we report a 36-year-old Chinese male patient with delayed-onset PFIC who presented with recurrent jaundice and pruritus. Laboratory investigations excluded viral, autoimmune, or neoplastic causes of liver injury. Liver biopsy demonstrated hepatocyte hydropic degeneration and intracanalicular bile thrombi, while genetic testing revealed compound heterozygous variants in the MYO5B gene: c.3604-1G>C and c.1165G>T (p.V389F). The patient exhibited fluctuating bilirubin levels refractory to initial therapies including corticosteroids, ursodeoxycholic acid, cholestyramine, and artificial liver support. However, bilirubin normalization was achieved following adjunctive traditional Chinese medicine therapy after transfer to our institution. This case highlights that genetic etiologies, particularly MYO5B-related disorders, should be considered in patients presenting with recurrent hyperbilirubinemia, pruritus, and hepatosplenomegaly after excluding common causes (viral, autoimmune, drug-induced, or tumor-related). Genetic testing for MYO5B mutations is warranted in cases of high bilirubin with normal/mildly elevated GGT levels, as early recognition is critical for timely intervention.