Is a cleft lip and palate caused by mutation, translation, deletion or duplication?

Cause unknown: This affects 1 in 700 births. It may be genetic or environmental and it is a birth defect that occurs while the fetus is forming in the early stages of pregnancy. There is a greater chance of this defect if it occurs in another family member.

All the above: The genetics for cleft lip and palate is only partially understood. There are a number of genetic mutations (deletions, duplications among them) that can be associated with clefting. There is no single genetic explanation.

Depends: There is no single specific defect that results in cleft lip or palate. There is some evidence as to hereditary and like transmission.