Metabolic Conditions Flashcards
When is the neonatal blood spot screening test performed?
5-9 days of life
What 9 conditions are screened for on the neonatal blood spot screening test?
1) Sickle cell
2) CF
3) Congenital hypothyroidism
4) Phenylketonuria
5) Medium chain acyl-CoA dehydrogenase deficiency (MCADD)
6) Maple syrup urine disease (MSUD)
7) Isovaleric acidaemia (IVA)
8) Glutaric aciduria type 1 (GA1)
9) Homocystinuria (pyridoxine unresponsive) (HCU)
Why is it important to diagnose and treat congenital hypothyroidism early?
If not diagnosed and treated within the first 4 weeks it causes irreversible cognitive impairment.
How soon must congenital hypothyroidism be treated to avoid irreversible cognitive impairment?
Within the first 4 weeks
Features of congenital hypothyroidism?
1) Prolonged neonatal jaundice
2) Delayed mental & physical milestones
3) Short stature
4) Puffy face, macroglossia
5) Hypotonia
What is phenylketonuria (PKU)?
An autosomal recessive condition caused by a disorder of phenylalanine metabolism.
There is a disorder of the metabolism of what in PKU?
Phenylalanine
Typical cause of PKU?
Defect in phenylalanine hydroxylase –> an enzyme which converts phenylalanine to tyrosine.
What can high levels of phenylalanine in PKU cause?
Learning difficulties & seizures
Which chromosome is the gene for phenylalanine hydroxylase located on?
Chromosome 12
Features of PKU?
1) usually presents by 6 months e.g. with developmental delay
2) child classically has fair hair and blue eyes
3) learning difficulties
4) seizures, typically infantile spasms
5) eczema
6) ‘musty’ odour to urine and sweat
What test is used to diagnose PKU?
Guthrie test –> ‘heel-prick’ test done at 5-9 days of life
What can be found in the urine in PKU?
phenylpyruvic acid
