May 13, 2021

Newborn screening in progress: a new analytical technique

A few drops of blood taken on the heel: this gesture seems banal but it is nevertheless one of the greatest successes of the 20th century medicine. Guthrie's test has changed the lives of thousands ofchildren, and of parents. Since its creation, nearly 35 million babies have benefited from this screening, and 19,000 young patients have been diagnosed and treated.

To date, in France, neonatal screening can detect five rare and potentially (very) serious diseases:

Cystic fibrosis (1 birth in 4000)
Cystic fibrosis is a disease that affects the respiratory tract and the digestive system. There is no treatment, however, early treatment can improve quality and life expectancy.

Phenylketonuria (1 in 15,000 births)
Phenylketonuria is one of the most common metabolic diseases. The absence of an enzyme does not allow the body to transform phenylalanine, acid present in certain foods (meat, fish, eggs, dairy products and starchy foods). In the absence of treatment (low phenylalanine diet), phenylketonuria causes mental retardation and neurological disorders.

Congenital hypothyroidism (1 birth in 4000)
Congenital hypothyroidism comes from a lack of thyroid hormone production. In the absence of treatment, this disease can causechild serious neurological lesions leading to irreversible sequelae (mental retardation, physical development halted ...).

Sickle cell disease (1 in 4000 births)
Sickle cell disease mainly affects populations in Africa, the West Indies, India, the Middle East and the Mediterranean Basin, particularly Greece and Italy. This disease prevents the proper functioning of hemoglobin and can lead to very serious complications if it is not supported as soon as possible.

Congenital adrenal hyperplasia (1 in 12,000 births)
Congenital adrenal hyperplasia is an abnormality of the adrenal glands located in the kidneys. In the absence of treatment, this disease causes various disorders such as disturbances of growth and puberty. If the disease is detected, thechild is immediately put on a corticosteroid.

Neonatal screening of tomorrow
Many other countries such as Germany and the Netherlands have chosen to expand neonatal screening. Some until the detection of thirty pathologies. However, the effectiveness of treatments for some of these diseases has yet to be proven. So we can not talk about the delay of the French system, but it is rather ethical questions, financial (to date, the test of Guthrie represents a cost of 6 euros per baby, the inclusion of new screening would greatly increase this cost) and organizational challenges to the evolution of neonatal screening. The goal is not only to diagnose but to be able to prevent and treat the consequences of each disease. In addition to the 50 pathologies that may be detected, there is also talk of identifying a genetic link with diseases such as asthma and diabetes. This evolution would also extend to the creation of a genetic database.

A new analytical technique: tandem mass spectrometry
Mass spectrometry (MS-MS) could soon detect 30 to 50 additional diseases with only 1 drop of blood. Several countries already use this technique.

Among these new discoverable pathologies, this extension of neonatal screening would make it possible to detect the congenital deficit in MCAD, a metabolic disease that affects one in 10,000 newborns. Without diagnosis or management, this disease can often be considered a death. Sudden Infant However, with a suitable treatment, the prognosis is very encouraging.

In 2011, the High Authority of Health has agreed to include this new screening, but its implementation in laboratories could take some time. Concerning the open doors on the various other pathologies: business to follow ...

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