What is amino acid disorder screening?
Amino acid disorder screening checks for inherited disorders in
amino acid metabolism. Tests are most commonly done on newborns.
Two tests are available, one using a blood sample and the other a
urine sample.
Newborn screening was first applied to the detection of
phenylketonuria (PKU) by a bacterial inhibition assay pioneered in
1961 by Guthrie, who was also responsible for the introduction of
the use of a dried blood sample. This
was followed by further bacterial inhibition assays to detect
other aminoacidopathies (maple syrup urine disease, homocystinuria,
urea cycle disorders and so on) but only screening for PKU was
widely adopted. In 1975 Dussault described screening for congenital
hypothyroidism (CH), and since then other disorders covered in some
screening programmes have included congenital adrenal hyperplasia,
the galactosaemias, cystic fibrosis, biotinidase deficiency,
glucose-6-phosphate dehydrogenase deficiency and many others.
The application of GCMS technology has changed the diagnostics in
metabolic disorders giving accurate results from a urine test. This
new technology has greatly changed both newborn screening and the
diagnosis of as many as 100 treatable inborn errors of metabolism
including the amino acid metabolism.