Children who have a small head size, facial and heart defects, lower intelligence, problems in learning, memory, hyperactivity, impulsivity, and communication and social skills may have been prenatally exposed to

Children who have a small head size, facial and heart defects, lower intelligence, problems in learning, memory, hyperactivity, impulsivity, and communication and social skills may have been prenatally exposed to: Congenital heart disease

Due to a couple of genetic mutation, a child could exposed to congenital heart disease before they're born. This disease will impair neurodevelopment of the child which will cause all of the symptoms above.