Signs and Symptoms of Phenylketonuria:

A newborn who has PKU will appear normal. By the age of four months, symptoms of arrested brain development will begin to appear. If the PKU is untreated, severe, irreversible mental retardation will occur.

• Signs and symptoms of PKU may include the following:

• abnormal movements, which may be writhing in nature

• behaviors resembling autism, which is a pervasive developmental delay

• decreased muscle tone

• difficulty walking

• a head that is smaller than normal in size

• learning disabilities

• a musty odor due to skin excretion of phenylacetic acid

• psychotic episodes, in which the person is unable to distinguish reality from fantasy

• rapid decrease in IQ in the first year of life

• seizures

• skin lesions or rough, dry skin