Newborn screening: what it is, when it is done, why it is important to do it

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Philippe Gloaguen
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Neonatal screening

Filippo, 4 years old in April, owes his life as a normal child, awake and lively, to a small blood sample, done in the hospital when he was only two days old. Philip, in fact, has themethylmalonic acidemia, a rare one metabolic disease which, if not treated, can lead to very serious consequences, including developmental delay, cognitive impairment, anemia, behavioral disturbances, cardiac malformations. Thanks to that sampling, necessary for the execution of a test called screening neonatale o metabolic screeningHowever, the worst was avoided, because together with the diagnosis of the disease, the solution also arrived: a cocktail of drugs and vitamins that prevents the manifestation of the damage associated with the disease itself and allows Filippo to have a completely normal existence.

In this article

  • Extended neonatal screening
  • What is neonatal screening and what is it for
  • What are the diseases that newborn screening deals with?
  • How can inherited metabolic diseases be treated?
  • How many children are affected?
  • How does newborn screening work: where is it done, when is it done, how is the outcome communicated?
  • Is expanded screening really happening everywhere today?
  • How do you know if the birthplace where you give birth offers expanded newborn screening?
  • New perspectives for the newborn screening test

Extended neonatal screening

Law 167 of 2022 provides for it for all children, whether born in a public hospital, in a private center or at home, at no cost to families, given that it has been included in the new essential levels of assistance, which came into force. last year. We asked Giancarlo La Marca, head of the neonatal screening laboratory of the Meyer Hospital of the city and president of the Del Paesena Society for the study of hereditary metabolic diseases and neonatal screening to clarify this topic.

What is neonatal screening and what is it for

The simple answer is that it is a biochemical test on a blood sample from a newborn, made to identify any symptoms before the onset hereditary metabolic diseases which, if not identified and treated in time, can lead to major and permanent clinical damage, such as mental retardation, or even a premature death.

If, on the other hand, the disease is identified and we start immediately with the appropriate treatment - as happened in the case of little Filippo - everything can change: quality and life expectancy drastically improve, up to the possibility of anormal existence (apart of course the need to take drugs or some limitations in the diet).

Time is of the essence, explains La Marca. If the damage has already occurred, it is generally impossible to go back or stop its progression: this is why we must act as soon as possible, recognizing the disease in the very first days of life.

The Marca, however, prefers one a little more articulated definition of newborn screening:

Not just a biochemical test, but a complex multidisciplinary system, which also provides forinformation to parents, the involvement of the staff who must take, store and send blood samples to the analysis laboratories, any diagnostic confirmation procedures and, in the event of a definitive diagnosis, the child's care by doctors or other expert specialists of the disease in question

Filippo's story: when newborn screening saves your life

An absolutely normal pregnancy, a quick and trouble-free birth, and finally, in April 2022, he arrives, Filippo, a newborn apparently in great shape. Roberta, the mother, does not know yet - she will be told at the time of her resignation - but when Filippo is two days old he is subjected to the test of expanded neonatal screening. His salvation.

Ten days after returning home, in fact, Roberta receives a phone call from the hospital: they tell her that the child has tested positive, in particular with respect to a substance called acetyl-carnitine. While reassuring her that she could have been a false positive they summon her for further tests and her mother's heart begins to get agitated: she tries to think positively, but "feels" that something would not have gone the right way.

In fact it is just like that: the new series of tests confirms that there is a problem and it has a difficult name, methylmalonic acidemia. A metabolic disease of genetic origin that could seriously and permanently compromise Filippo's development. Luckily there is a solution: a cocktail of drugs and vitamins to be taken by mouth or with intramuscular injections: cystadane, vitamin B12, vitamin B6, folic acid and carnitine. The therapy, started immediately, works: the levels of toxic substances caused by the disease begin to drop. Four years later, Filippo is a perfectly normal child: he talks (he could not have done it), runs, plays, goes to kindergarten.

When she talks about her son's problem, Roberta often hears the answer "but it doesn't seem like it!". She has learned to have the answer ready: "It doesn't seem like she was lucky enough to have one diagnosis at birth. Otherwise now we would be fighting another battle, certainly harder and more difficult than this one. "

That's why Roberta has become a staunch supporter of newborn screening, of which she talks about its importance every time she gets the chance:

When a woman is pregnant she hears about many things, some as important as the preservation of the cord, others more superficial. But very little is said about newborn screening and those metabolic diseases which, if discovered in time, can still be dealt with in an excellent way, guaranteeing a normal life instead of very heavy damage ".

Read also: First birth checks

What are the diseases that newborn screening deals with?

As early as 1992, mandatory neonatal screening was conducted throughout the country for the identification of three hereditary diseases:

  1. phenylchetonuria,
  2. cystic fibrosis,
  3. congenital hypothyroidism.

To these three diseases some regions had over time added others, arriving at a panel "enlarged": a condition that had however generated a strong one inequality on a purely geographical basis in terms of opportunities for treatment and, at times, for salvation. In 2022 there was much talk about the dramatic case of Malika, who died at just four months from the Pompe disease, a serious and very rare neuromuscular disease. In Emilia of the city, where the child was born and resided, the disease was not included in the screening, while even then it was for example in Tuscany: if it had been identified at birth, Malika would probably be alive today.

The law of 2022 made the so-called expanded screening mandatory in all regions and, therefore, for all children

The diseases involved are more than 40: the complete list can be consulted in the Official Gazette. "In general we can say that they all belong to the group of hereditary metabolic diseases o inborn errors of metabolism, a group of genetic diseases caused by the failure of a metabolic pathway "explains La Marca.

A metabolic pathway is a set of biochemical transformations that allow to pass from some substances possibly derived from food (the substrates) to other substances that serve specific cellular tasks (the products). These transformations are accomplished by proteins called enzymes. If an enzyme malfunctions or malfunctions, because there is an alteration in the DNA sequence that carries the information to build it, metabolic disease arises.

"The possible consequences are mainly two" explains the expert. "On the one hand, theaccumulation of substrates which are not processed properly and are often very toxic for the organism; on the other the lack of products and therefore of the function they perform, sometimes fundamental. The damage caused by the disease may depend on only one of these effects or on both. "Generally, the symptoms are systemic, that is, they affect multiple organs and systems and the nervous system.

Among the examples, La Marca cites the organic aciduria, such as methylmalonic acidemia and fatty acid beta-oxidation defects, a possible cause of sudden infant death. "However, if they are identified at birth, a modification of the diet is enough to allow an absolutely normal life".

How can inherited metabolic diseases be treated?

Treatment for these diseases can usually include some dietary interventions or the administration of medications, vitamins or enzymes, or both. "These are not - explains La Marca - definitive cures, but tools that in any case allow to neutralize in whole or in part the metabolic defects responsible for damage to the body".

For example: in the case of phenylchetonuria, which involves the inability to metabolize the amino acid phenylalanine, is bet on one low protein diet, therefore with few foods of animal origin, and rich in unsaturated fats and on the possible administration of protein supplements without phenylalanine (indications from European guidelines on phenylketonuria). In the case of the Pompe diseaseInstead, enzyme replacement therapy is used: in practice, the body is supplied with the enzyme that the disease prevents it from producing.

How many children are affected?

"Taken individually, these diseases are rare or very rare, but if we consider them all together, the load is very significant "explains La Marca." Considering the bulk of the diseases on the list of law and excluding phenylketonuria and hypothyridism, more known and frequent, it is estimated a new case every 1500 births about".

It means about 350 children a year, in Del Paese, are born with a sort of time bomb in their bodies: a disease that could seriously compromise their future, but which, thanks to expanded newborn screening, can be promptly recognized and treated.

How does newborn screening work: where is it done, when is it done, how is the outcome communicated?

"Extended screening must be done in a very specific time window, that is between 48 and 72 hours after birth"La Marca affirms. If done before it could give unreliable results, because perhaps the various enzyme systems of the newborn are not yet well stabilized. If done later, however, for some diseases there is the risk that it is already too late.


Blood sampling is performed via a small puncture on the baby's heel. Her ideal would be to give it to him while her baby is in her mother's arms, so that she can console him for the annoyance, perhaps by attaching him to her breast. A strategy that also allows you to explain to the mother - if it was not done before as she should have - what neonatal screening consists of and why it is important to do so, or to clarify any doubts. We remember in fact that, being one mandatory procedure by law, the signature of a informed consent from parents before performing it.

The few drops of collected blood are transferred to a paper towel, which is sent to a reference laboratory in the region for expanded screening. From now on, if all goes well - that is, if it is screening is negative and does not show any anomalies - the parents no longer know anything. "The data will be recorded in the medical record of the newborn, but the family will not receive additional communications".

If instead the test is positive, indicating that there may be something wrong, the parents are called back for further investigations. "The sampling is being redone and new, more specific and detailed tests are carried out, which make it possible to clarify the situation" explains La Marca. Sometimes, in fact, it happens that the one obtained with the screening is only a false positive, while subsequent investigations clarify that in reality the disease does not exist.

Warning: receiving a phone call that warns of a positive screening test does not mean that your baby is definitely sick: it could be a false positive. In these cases, further investigations must be carried out

"Depending on the severity of the suspected disease, the child and his / her family may be called back for examination either at the birthplace where the screening was performed, or at a referral center for the disease itself." If the diagnosis is confirmed, the newborn is immediately taken care of by a team of doctors who are experts in his condition, generally, in the case of rare diseases, at specific reference centers.

Courtesy Telethon Foundation

Is expanded screening really happening everywhere today?

Unfortunately the answer to this question is "no, not yet". According to data from the screening coordination center of the Higher Institute of Health, Calabria is still missing and, according to La Marca, "this is also missing in other regions. valuable prevention activity it is not yet well structured ".

What to do, then, in these cases? To begin with, parents need to be aware that the newborn screening test is a right of their child, and a valuable tool for safeguarding their health. Therefore, if mum and dad notice that it is not carried out, they certainly have the right to request it. If the structure does not offer the service, they can still request the collection and sending of the cardboard to the regional reference laboratory, for aexecution of the analysis at their expense: "The total cost is around fifty euros, one euro per sickness" says La Marca.

Alternatively, they can request the free test to be performed at the specific service of theAssociazione Del Paesena supporting hereditary metabolic diseases (Aismme): just ask the association to send the card you need to take the test (it will arrive with the instructions to follow) and then forward it to the Policlinico Umberto I of the city, which through the agreement with Aismme will offer the service for free. .

How do you know if the birthplace where you give birth offers expanded newborn screening?

Just ask for information at the center itself, or from the doctor who follows the pregnancy. Alternatively, you can also ask the geneticists of Telethon's Info_Rare online service or Aismme.

Extended neonatal screening: the 3 things you need to know

It's not just screening coverage that's still lacking a bit. Information is too, and there are not a few families who know practically nothing about this test.

Here is the essential information, in the opinion of Giancarlo La Marca:

1. Newborn screening there: it is a very efficient preventive medicine service;
2. Newborn screening is not a duty, but a right for all children born in Del Paese;
3. Newborn screening allows many babies with a major genetic disease to lead a normal life, avoiding disastrous or dramatic situations.

New perspectives for the newborn screening test

The diseases envisaged by the law for expanded screening are a starting point, but certainly not an end point. For example, the Marca underlines how important it could be to include other rare diseases such as immunodeficiency as soon as possible Ada-Scid, which prevents the body from effectively fighting infections, or the leucodistrofia metacromatica, neurodegenerative disease that literally sends the nervous system into a tailspin, with progressive deterioration of motor and cognitive functions.

In these cases, a diet or drugs are not enough to solve or stop the situation, a more sophisticated therapy is needed: gene therapy. In the case of Ada-Scid this is already available: developed in Del Paese by researchers from the San Raffaele Telethon Institute for Gene Therapy in our city, it is now freely marketed in Europe. On the other hand, the La Marca team has developed an effective and economical screening test for the disease, so everything is ready to get it back on the list as soon as possible.

There is also a gene therapy for metachromatic leukodystrophy, although still experimental (they have also developed it at San Raffaele-Telethon for gene therapy). In this case, an early diagnosis would be even more important, because the chances of stopping the progression of the disease are higher the sooner the therapy is administered. On the screening front, however, there is still some work to be done: La Marca and colleagues have developed a test that has yet to be validated in a pilot study.


  • Information material Società Del Paesena for the study of Hereditary Metabolic Diseases and Neonatal Screening;
  • information pages of the Bambino Gesù Children's Hospital in the city (metabolic diseases and newborn screening);
  • Telethon information material
  • CBLC onlus
  • Official Journal

  • rare diseases
  • newborn 0-3 months
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