They will also study oral cancer and birth defects such as cleft lip and cleft palate.

BBC: Oral health research funding for Scottish universities

One of the ingredients in Qsymia is topiramate, an anti-convulsant that has been linked to birth defects such as cleft lip and cleft palate in babies born to women who have taken it for migraines or seizures.

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Gareth Davies, Chief executive of the Cleft Lip and Palate Association, said past studies had indicated that taking folic acid may help prevent cleft lip and palate in so called "high risk" groups but until now there had been no conclusive evidence to back this up.

BBC: Folic acid 'cuts cleft palate risk'

The study from the Centers for Disease Control and Prevention found IVF babies suffered from higher rates of conditions such as heart valve defects, cleft lip and palate, and digestive system abnormalities.

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PVRL1 plays a part in forms of cleft lip and palate which involve more than one gene.

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Fenske, a medical technician, and her husband, Kevin, an aircraft maintenance manager, were matched in July 2008 with an infant Kyrgyz girl afflicted by a severe cleft lip and palate.

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There is a strong genetic link - a baby is 30-40 times more likely to develop cleft lip and palate if their elder brother or sister was also born with the condition.

BBC: Folic acid 'cuts cleft palate risk'