Transports folate across the inner membranes of mitochondria (PubMed:15140890, PubMed:29666258). Can also transport FAD across the mitochondrial inner membrane (PubMed:16165386). Ubiquitous. The disease is caused by variants affecting the gene represented in this entry. Disease susceptibility is associated with variants affecting the gene represented in this entry. Belongs to the mitochondrial carrier (TC 2.A.29) family.