Risk factors for inheriting phenylketonuria include:

  • Having two parents with a defective PKU gene. Both parents must pass along a copy of the mutated PKU gene for their child to develop the condition.
  • Being of certain ethnic decent. The gene defect varies by ethnic groups and is less common in African-Americans than in other ethnic groups.

Children of mothers with PKU who didn't follow the PKU diet during pregnancy are at risk of birth defects due to the high levels of phenylalanine in their mothers' blood.

Oct. 17, 2017