Causes of Cleft

There is no single cause of cleft lip and/or palate. In most cases, a cleft is caused by lots of different factors (including genetics and the environment) coming together in a way that usually can’t be predicted or prevented. It is very unlikely that your baby’s cleft is because of something you did or didn’t do.
Around one in 700 babies are born with a cleft around the world. That’s three every day. Annually in Pakistan, over 9000 newborns (or about one in 530 babies) are born with a cleft.

Around 15% of clefts are caused by syndromes, where one or more symptoms occur altogether. If a syndrome is involved, the chances of passing on a cleft are all down to the heritability of the syndrome, which in some cases can be as high as 50%.

An isolated cleft palate (where the lip is not affected) is believed to have a different cause to cleft lip and palate. So a family affected by cleft palate (but not cleft lip) may only be likely to pass on cleft palate.
There are a huge number of factors that affect how likely someone is to have a cleft, including race, sex, and many different environmental factors that are almost impossible to predict without a careful look at an individuals genetic history and circumstances.