Final answer:
Phenylketonuria (PKU) is the genetic disorder that causes central nervous system damage due to high levels of phenylalanine in the blood. It requires a low-phenylalanine diet to prevent symptoms and is tested for in newborns across the United States and Canada.
Step-by-step explanation:
The genetic disorder that causes central nervous system injury from toxic levels of the amino acid phenylalanine in the blood is Phenylketonuria (PKU). PKU is a condition where the enzyme phenylalanine hydroxylase is deficient, preventing the adequate breakdown of phenylalanine into tyrosine. This deficiency leads to a toxic accumulation of phenylalanine, which can result in brain and central nervous system damage. A strict low-phenylalanine diet is required to manage the condition and prevent the symptoms, which can include delayed neurological development, mental disabilities, seizures, tremors, and hyperactivity.
It is important to note that every newborn in the United States and Canada is tested for PKU so that treatment can begin early if needed. Pregnant people with PKU need to be particularly careful since high levels of phenylalanine can harm the developing fetus. Some foods and artificial sweeteners high in phenylalanine, such as aspartame, must be avoided to keep blood phenylalanine levels safe.