BCAA's need to be monitored regularly. PKU is inherited as an autosomal recessive disorder. Classic PKU is caused by a deficiency in phenylalanine hydroxylase. Blood tests are now mandated within 2-3 days after a child is born. Urinary testing may also be undertaken.
Therapy is to reduce phe in the diet.
It is common in eastern European Jews. Onset of the disease occurs at about 3-6 months of age. Death usually occurs by age 2-3 years. Diagnostic testing is available. Therapy seems to be symptomatic.