Anti-C6orf138 antibodies enable researchers to detect and measure the C6orf138 antigen in biological samples. This target is a reported synonym of the PTCHD4 gene, which encodes patched domain containing 4. This protein is suspected to act as a repressor of canonical hedgehog signaling by antagonizing the effects of SMO, as suggested by down-regulation of hedgehog target genes, including GLI1, PTCH1, and PTCH2 in PTCHD4-expressing cells. The human version of C6orf138 has a canonical amino acid length of 846 residues and a protein mass of 96.4 kilodaltons, although 4 isoforms have been identified. It is reported to be localized in the membrane of cells. C6orf138 is a member of the Patched protein family.