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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One of the boys, the twelve-year-old Alex Libby, was born prematurely and now has a slightly curved and flattened upper lip.

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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.

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