SLC46A1 and craniofacial microsomia: Hereditary folate malabsorption (HFM) is a rare, autosomal recessive disorder characterized by impaired intestinal absorption and impaired transport of folates across the choroid plexus into cerebral spinal fluid due to inactivating mutations in the human proton-coupled folate transporter (hPCFT) gene, which encodes the proton-coupled folate transporter (PCFT) SLC46A1.