[5] SMAD6 is a protein that, as its name describes, is a homolog of the Drosophila gene "mothers against decapentaplegic".

It acts as a regulator of TGFβ family (such as bone morphogenetic proteins) activity by competing with SMAD4 and preventing the transcription of SMAD4's gene products.

The phrase "Mothers against" was added as a humorous take-off on organizations opposing various issues e.g., Mothers Against Drunk Driving, or MADD; and based on a tradition of such unusual naming within the gene research community.

[6] Heterozygous, damaging mutations in SMAD6 are the most frequent genetic cause of non-syndromic craniosynostosis identified to date.

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