A homozygous R148W mutation in Semaphorin 7A causes progressive familial intrahepatic cholestasis
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ABSTRACT: Semaphorin 7A (SEMA7A) is a membrane-bound protein that involves axon growth and other biological processes. SEMA7A mutations are associated with vertebral fracture and Kallmann syndrome. Here we report a case with a mutation in SEMA7A that displays familial cholestasis. WGS reveals a SEMA7A_R148W homozygous mutation in a female child with elevated levels of serum ALT, AST, and total bile acid (TBA) of unknown etiology. This patient also carried a SLC10A1_S267F allele, but Slc10a1_S267F homozygous mice exhibited normal liver function. Similar to the child, Sema7a_R145W homozygous mice displayed elevated levels of serum ALT, AST, and TBA. Remarkably, liver histology and LC-MS/MS analyses exhibited hepatocyte hydropic degeneration and increased liver bile acids (BA) levels in Sema7a_R145W homozygous mice. Further mechanistic studies demonstrated that Sema7a_R145W mutation reduced the expression of canalicular membrane BA transporters, bile salt export pump (Bsep) and multidrug resistance-associated protein-2 (Mrp2), causing intrahepatic cholestasis in mice. Administration with ursodeoxycholic acid and a dietary supplement glutathione improved liver function in the child. Therefore, Sema7a_R145W homozygous mutation causes intrahepatic cholestasis by reducing hepatic Bsep and Mrp2 expression.
SUBMITTER: Qiong Pan
PROVIDER: S-SCDT-EMM-2021-14563 | biostudies-other |
REPOSITORIES: biostudies-other
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