GWAS of serum ALT and AST reveals an association of SLC30A10 Thr95Ile with hypermanganesemia symptoms

To investigate mechanisms of hepatocellular damage, we performed genome-wide association studies (GWAS) on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serum activities across 411,048 subjects from four ancestry groups in the UK Biobank, and found 100 loci associating with both enzymes. The rare missense variant SLC30A10 Thr95Ile (rs188273166) associates with a larger elevation in ALT and AST than any other variant tested and this association also replicates in the DiscovEHR study. SLC30A10 excretes manganese from the liver to the bile duct, and rare homozygous loss of function causes the syndrome hypermanganesemia with dystonia-1 (HMNDYT1) which involves cirrhosis. Consistent with hematological symptoms of hypermanganesemia, SLC30A10 Thr95Ile carriers have increased hematocrit and risk of iron deficiency anemia. Carriers also have increased risk of extrahepatic bile duct cancer. These associations suggest that genetic variation in SLC30A10 adversely affects more individuals than patients with diagnosed HMNDYT1.