Phenylketonuria Flashcards
1
Q
recessive or dominant
A
autosomal recessive
2
Q
what is it?
A
an autosomal recessive condition caused by a disorder of phenylalanine metabolism.
This is usually due to defect in phenylalanine hydroxylase, an enzyme which converts phenylalanine to tyrosine.
3
Q
gene
A
gene for phenylalanine hydroxylase is located on chromosome 12
4
Q
features
A
usually presents by 6 months e.g. with developmental delay
child classically has fair hair and blue eyes
learning difficulties
seizures, typically infantile spasms
eczema
‘musty’ odour to urine and sweat*
5
Q
Ix
A
Guthrie test - heel prick test 5-9 days
hyperphenylalaninaemia
phenylpyruvic acid in urine
6
Q
Mx
A
dietary restrictions during pregnancy
