inborn error of amino acid metabolism pathway hyperhomocysteinemia pathway 2015-08-24T16:01:46Z A condition of elevated levels of homocysteine usually due to alteration in folate metabolic pathways. Homocysteine is an intermediate in the methionine metabolic cycle. It can be remethylated to methionine or it can follow the transsulfuration pathway. PW:0001840 hyperhomocysteinemia disease pathway pathway vpetri