Enables NADP binding activity; flavin adenine dinucleotide binding activity; and methylenetetrahydrofolate reductase (NAD(P)H) activity. Involved in several processes, including homocysteine metabolic process; response to interleukin-1; and response to vitamin. Located in cytosol and synapse. Biomarker of hyperthyroidism; hypothyroidism; and liver benign neoplasm. Human ortholog(s) of this gene implicated in several diseases, including autoimmune disease (multiple); carcinoma (multiple); cardiovascular system disease (multiple); hematologic cancer (multiple); and kidney failure (multiple). Orthologous to human MTHFR (methylenetetrahydrofolate reductase). [provided by Alliance of Genome Resources, Apr 2022]