Download 8 phenylketonuria facts - Centre for Genetics Education

8
DProduced
by the Centre for Genetics Education. Internet: http://www.genetics.edu.au
PHENYLKETONURIA
Produced by the Centre for Genetics Education. Internet: http://www.genetics.edu.au
Includes: PKU, PKU I (phenylalanine hydroxylase deficiency), PKU II (dihydropteridine reductase deficiency), Hyperphenylalanaemia
FACTS
Phenylketonuria (PKU) is an inborn error of metabolism. It is caused by the lack of an enzyme involved in the metabolism of the amino
acid, phenylalanine. Symptoms are not usually seen in newborns. Babies with PKU may be unusually drowsy and have difficulty feeding.
Untreated infants may have light pigmentation in the eyes, skin, and hair and often develop a rash. Accumulation of phenylalanine, or
some of its by-products in the body, leads to intellectual impairment. PKU follows an autosomal recessive pattern of inheritance. There are
different types of PKU depending on which enzyme in the PKU pathway is deficient or not working properly. The gene involved in PKU1 is
called PAH, and is located on the long ‘q’ arm of chromosome 12, at 12q24.1. The gene causing PKU2 is located on the short ‘p’ arm of
chromosome 4, at 4p15.31. Another type of PKU is caused by a faulty gene on the long ‘q’ arm of chromosome 11, at 11q22.3-q23.3.
A specially prescribed low protein diet, together with phenylalanine free supplements, will prevent intellectual impairment if begun very
early in life. It is of particular importance for pregnant mothers with PKU, to maintain a strictly controlled diet both before and during
pregnancy, since this may have implications for a baby’s development.
In Australia and New Zealand, newborn screening for PKU is carried out on all babies 3 to 5 days after birth, for early diagnosis.
Support Groups can provide individuals and families with information about genetic conditions, community resources and an
understanding and empathic ear.
If you are not able to contact the services listed below, please call the Association of Genetic Support of Australasia (AGSA) on
(02) 9211 1462 or visit www.agsa-geneticsupport.org.au for support and assistance.
Further information and details of your local genetic counselling service can be found at www.genetics.edu.au, or please call
The Centre for Genetics Education on (02) 9462 9599.
www.genetics.edu.au
© Centre for Genetics Education
1