A disorder of phenylalanine hydroxylation leading to the accumulation of the amino acid phenylalanine. Undiagnosed individuals show progressive developmental delay in the first year of life, mental retardation, seizures, autistic-like behavior and a peculiar body odor. Incidence 1 in 10,000 to 1 in 25,000. Potential for symptomatic diagnosis without genetic screening Rarely diagnosed before 6 months old, after which time mental retardation is obvious. Genetic Counseling Information is available by state screening programs and is often mandated by state regulations or laws.
Counseling is available for the family of an identified individual.
Clinical Outcome without Screening and Treatment Lifespan expectancy is reduced. Convulsions and hyperactivity are common among untreated individuals. Clinical Outcome with Screening and Treatment Normal early growth and development are expected. Normal range of intelligence is possible with optimal dietary control. Dietary control needs to be maintained throughout life.