Phenylketonuria (PKU). Phenylalanine hydroxylase deficiency.
Incidence
1:14.000, Autosomal recesive
Clinical Characteristics
Normal at birth. Vomiting and irritability first 2 months. Decreased IQ by 4-9 months. Seizures 4-18 months. Infantile Spasms, Hypsarrythmia. Then T-C seizures. Severe mental retardation. Blond, blue eyes, dry skin, eczema, rat urine (musky) body odor, microcephaly, mild tremor in 30%. By 9 to 10 years, children are hyperactive, with mannerisms and autistic behavior.
Precipitants
None. There are no acute crisis.
Provocation Tests
Administration of evaporated milk formula x 3 days elevates ser. phenylalanine and urine metabolites. Not recommended.
Diagnostic Procedures
Ferric chloride gives emerald green transient color. Tandem MS, HPLC aminoacids. No biopsy necessary