Regarding Genetic Causes of Intellectual Disabilities,which of the Following Statements

Regarding genetic causes of intellectual disabilities,which of the following statements is FALSE?

A) Down syndrome children have an extra X chromosome in the 23rd pair.
B) Although Down syndrome is genetic,it is not usually hereditary,that is it doesn't "run in the family."
C) Children with PKU (phenylketonuria) have an inherited inability to control a destructive chemical that builds up in their bodies.
D) Individuals with Down syndrome have almond-shaped eyes,a slightly protruding tongue,a stocky build,and stubby hands with deeply creased palms.