What is the cause of cleft lips and palates?
Cleft lip and palate are birth defects that affect the upper lip and the roof of the mouth. Genetics are not always the cause of this birth defect.
There are many causes. Problems with genes passed down from one or both parents, drugs, viruses, or other toxins can all cause these birth defects.
Cleft lip and palate may occur along with other syndromes or other birth defects.
Risk factors include a family history of cleft lip or palate and other birth defects.
There may be a cleft (split) just of the lip, just of the palate, or both. They can be one-sided (unilateral) or double-sided (bilateral).
Many genes are known to play a role in craniofacial development.
In humans, fetal cleft lip has also been linked to maternal hypoxia, as caused by maternal smoking or maternal alcohol abuse.
Other environmental factors that have been studied include:
pesticide exposure, diet and vitamin intake, anticonvulsant drugs, organic solvents, maternal exposure to lead, and illegal drugs (cocaine, crack cocaine or heroin).