Phenylketonuria
How PKU is inherited
The genetic cause (mutation) responsible forPKU is passed on by the parents, who are usually carriers and don't have any symptoms of the condition themselves.
The way this mutation is passed on is known as autosomal recessive inheritance. This means a baby needs to receive two copies of the mutated gene to develop the condition one from their mother and one from their father. If the baby only receives one affected gene, they'll just be a carrier of PKU.
If you're a carrier of the altered gene and you have a baby with a partner who's also a carrier, your baby has:
- a 25% chance of inheriting the condition
- a 50% chance of being a carrier of PKU
- a 25% chance of receiving a pair of normal genes
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Read about phenylketonuria (PKU), a rare genetic condition that's present from birth (congenital), where the body is unable to break down phenylalanine.
Diagnosing PKU
At around five days old, babies are offered newborn blood spot screening to check if they have PKU or a number of other conditions. This involves pricking your baby's heel to collect drops of blood t
Symptoms of PKU
PKU doesn't usually cause any symptoms if treatment is started early. Without treatment, PKU can damage the brain and nervous system, whichcanlead to learning disabilities. Other symptoms of untreat
TreatingPKU
Diet The main treatment for PKU is a low-protein diet that completely avoids high-protein foods such as meat, eggs and dairy products and controls the intake of many other foods, such as potatoes a
How PKU is inherited
The genetic cause (mutation) responsible forPKU is passed on by the parents, who are usually carriers and don't have any symptoms of the condition themselves. The way this mutation is passed on is kn
Adults with PKU
Manyadults with PKU find they function best while on a low protein diet. The current advice is for people with PKU to remain on a low protein diet for life. However, this wasn't always the case in th
PKU and pregnancy
Women with PKU have to take particular care during pregnancy, because high levels of phenylalanine can damage the unborn baby. Providing that phenylalanine levels are strictly controlled during pregn
Information about you
If you or your child has PKU, your clinical team will pass information about youon to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS). This helps scientists look for
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