Hyperammonaemia in ACLD is driven by ammonia overproduction/altered microbiome in the intestinal tract,6,7 decreased metabolic capacity in the hepatocytes leading to a reduced ammonia metabolism in the urea cycle and via glutamine synthetase,8,9 and portal hypertension through the development of portosystemic shunting via collateral flow.10 The gene discussed is GLUL; the disease is portal hypertension.