What is Newborn Screening?
In the UK, babies are screened via the heel prick test (also known as the blood spot or Guthrie test) at 5 days of age. A midwife visits the family home and takes a blood sample by making a small prick on the baby’s heel. The blood sample is then sent to a laboratory where scientists analyse it for nine rare disorders. Six of these conditions are Inherited Metabolic Disorders:
Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD)
Maple Syrup Urine Disease (MSUD)
Isovaleric Acidaemia (IVA)
Glutaric Aciduria Type 1 (GA1)
There are three potential outcomes from the heel prick test:
- Normal – the vast majority of babies have clear results and the parents should receive a letter confirming this several weeks after the test.
- Insufficient – sometimes another sample needs to be taken so that the laboratory can perform the tests again – this can be for a number of reasons and there is usually nothing wrong.
- Abnormal – in very rare cases the tests show abnormal results which indicate the baby may have one of the nine disorders. If this happens, the parents will be contacted by a specialist to arrange for a second test at a regional centre to confirm the result. If the second result shows that the baby does have the suspected disorder, advice will be given on the next steps, including treatment and management. Our Newborn Screening app is an interactive resource providing information and advice for new parents following an abnormal result.
About 1 in 10,000 babies born in the UK has PKU or MCADD. The other conditions are rarer, occurring in 1 in 83,000 to 100,000 babies. Each year, approximately 176* babies in the UK receive a positive diagnosis via the Newborn Screening Programme.
Without treatment, babies with Inherited Metabolic Disorders can become suddenly and seriously ill. Early diagnosis via Newborn Screening enables babies with these conditions to receive treatment or dietary management immediately, improving their health outcomes and preventing severe developmental problems, life-threatening symptoms or even death. If a baby is found to have an Inherited Metabolic Disorder, they will be placed under the care of a Specialist Consultant and supported by at tailored team of Healthcare Professionals at a regional centre in the UK.
*Approximate number based on extrapolated data pending completed and verified data collection. Numbers in any given year will vary (as at February 2019)
Why are so few Inherited Metabolic Disorders screened for?
The criteria and standards for screening are set and monitored by the National Screening Committee and Public Health England. Considerations and evidence required include:
- There should be an acceptable treatment for patients with the disease
- The facilities for diagnosis and treatment should be available
- There should be a recognised latent or early symptomatic stage
- There should be a suitable test or examination which has few false positives and few false negatives
- The test or examination should be acceptable to the population
- The cost, including diagnosis and subsequent treatment, should be economically balanced in relation to expenditure on medical care as a whole
Metabolic Support UK sit on the NHS Inherited Metabolic Disorders Screening Advisory Board, and continue to support developments in Newborn Screening and other diagnostic approaches.
If your child has been diagnosed with an Inherited Metablic Disorder via Newborn Screening, we can offer emotional support, practical advice and connect you with other families. Please contact us for more information on our services.