This family contains many hypothetical proteins. It also includes four nematode prion-like proteins. This domain has been identified as part of the nucleotidyltransferase superfamily .
The function of FAM46 family is not clear. FAM46 family members contain a NTase (nucleotidyltransferase) domain, some members possess additional C-terminal PAP/OAS1 substrate binding domain [PUBMED:19833706]. They have different functions in many tissues at various stages of development. Human FAM46A is a SMAD signalling pathway related protein, where SMADs are intercellular effectors of transforming growth factor-beta (TGF-beta) [PUBMED:19833706]. Human FAM46C seems to enhance replication of some viruses, including yellow fever virus, in response to type I interferon [PUBMED:17803723].