Overview
• Autosomal recessive metabolic genetic disorder
• Mutation in the gene for phenylalanine hydroxylase(PAH).
• When PAH activity is reduced, phenylalanine accumulates and is converted into
Etiology
• Autosomal recessive disorder caused by mutation in PAH gene
• Located on 12th chromosome.
• A carrier does not have symptoms of the disease, but can pass on the defective gene to his or her children.
Symptoms
• Most babies with phenylketonuria appear healthy at birth.
• Symptoms usually only develop due to complications that arise if the condition is not treated properly.
• If it isn't treated, damage to the brain and nervous system can lead to:
1. learning disabilities
2. behavioural difficulties
3. epilepsy
Symptoms
• Often have lighter skin, hair, and eyes than brothers or sisters without the disease.
• Other symptoms include:
-Eczema
-Recurrent vomiting
-Jerking movements in arms and legs
-Tremors
-Mood disorders
-Microcephaly,
Diagnosis
• Screening on blood samples during the first week of life.
• If a diagnosis of PKU is confirmed, the child will need regular blood tests to measure levels of phenylalanine in their blood and assess how well they are responding to treatment.
Treatment
• Phenylketonuria (PKU) can be successfully treated with a low-protein diet and dietary supplements.
• The diet must be strictly followed.
• Those who continue the diet into adulthood have better physical and mental health.
Prognosis
• The outcome is expected to be very good if the diet is closely followed, starting shortly after the child's birth.
• If treatment is delayed or the condition remains untreated, brain damage will occur.
• If proteins containing phenylalanine are not avoided, PKU can lead to intellectual disability by the end of the first year of life.