The function of ALDH1L2 (aldehyde dehydrogenase 1 family member L2, Ensembl gene identifier ENSG00000136010) is as follows. Mitochondrial 10-formyltetrahydrofolate dehydrogenase that catalyzes the NADP(+)-dependent conversion of 10-formyltetrahydrofolate to tetrahydrofolate and carbon dioxide. {ECO:0000269|PubMed:21238436, ECO:0000269|PubMed:38193334}.