Neonatal screening, also known as the Guthrie test, is carried out following parental consent through a heel prick of the newborn, within 48 to 72 hours of birth.
The few drops of blood taken are placed on blotting paper, which is then sent to a specialized laboratory to search for the presence of any pathologies.
Until 2020, five diseases were researched: “phenylketonuria, congenital adrenal hyperplasia, hypothyroidism, cystic fibrosis and, for newborns with risk factors, sickle cell disease”indicates the High Authority for Health (HAS).
In late 2020, medium-chain fatty acid acyl-CoA dehydrogenase (MCAD) deficiency was added to the list.
Hereditary metabolic diseases
Common point of these diseases: they are rare, serious, and most often of genetic origin. The challenge of neonatal screening is therefore to identify them very early, even before the appearance of the first symptoms, in order to implement “appropriate measures to avoid or limit the negative consequences of these diseases on the health of children” and ultimately improve their quality of life.
It is in this perspective that the HAS recommended including seven new pathologies in the neonatal screening program. These are all hereditary metabolic diseases (or “inborn errors of metabolism”) for which effective treatments exist and allow good development of the baby and then of the child.
Since 1is January, seven new pathologies are therefore screened:
- l’homocystinurie, “a vitamin B12 abnormality characterized by anemia, brain neurological damage and sometimes developmental delay”details Medicare;
- the leucinosea disease characterized “by eating difficulties, excessive sleep time, vomiting then neurological brain disorders and respiratory failure in the absence of treatment” ;
- type 1 tyrosinemia which affects the kidneys and the liver;
- isovaleric aciduriaresponsible “Acute disorders at birth (vomiting, convulsions) or later disorders (growth and/or development delay)” ;
- glutaric aciduria type 1 which causes acute neurological disorders in infants;
- long-chain fatty acid 3-hydroxyacyl-coenzyme A dehydrogenase deficiency, “characterized by the onset in early childhood of hypoglycaemia which may cause liver damage and heart damage” ;
- carnitine uptake deficiencywho trains “cardiac involvement in early childhood, often associated with hypotonia, growth retardation, recurrent hypoglycaemic attacks and/or coma”.
According to figures from Medicare, in 2021, neonatal screening “made it possible to diagnose 1,165 sick children, i.e. an incidence of 1 sick child for 641 children screened”.
Since the introduction of neonatal screening 50 years ago, more than 37 million children have been screened in France and nearly 30,000 have been treated quickly.