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Newborn screening -

Newborn screening is the name given to a public health program adopted by numerous countries across the world. The aim of the program is to screen newborns for a number of medical conditions.

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How it all started -

The roots of the program go back to the 1960s, when screening for an amino acid disorder called phenylketonuria (PKU) began.

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PKU screening -

American microbiologist Robert Guthrie was a pioneer in the early screenings for PKU. Shortly afterwards, the test was part of the public health program in the United States (and was later adopted by other nations).

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PKU screening -

Newborns with PKU are unable to metabolize a protein called phenylalanine. If left untreated, it may result in intellectual disability.

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Newborn blood spot screening test -

Like today, the test involved blood taken from a newborn’s heel to be placed on a specific filter paper. The sample is usually taken within 24-48 hours after the baby is born.

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New addition -

In the 1970s, congenital hypothyroidism, which is a thyroid hormone deficiency, was added to the newborn screening program. This condition can lead to mental development issues and affect growth.

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Development -

Over the years, many other tests were added, including the screening for maple syrup urine disease (when the the body cannot process certain amino acids) and classic galactosemia (which can result in feeding difficulties and severe liver disease), as well as numerous congenital metabolic diseases.

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Newborn screening varies, depending on the country -

Newborn screening programs around the world are all different. Some countries screen for numerous conditions, while others only test for as little as one or two conditions.

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Types of conditions -

We have mentioned a few conditions that newborns are screened for, namely PKU. Now, let’s look at some other tests that are also run, albeit not universally.

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Types of conditions -

Newborn screening can include screening for fatty acid oxidation disorders, amino acid metabolism disorders, organic acid metabolism disorders, endocrine disorders, hemoglobin disorders, congenital heart defects, urea cycle disorders, and hearing loss, among others.

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Fatty acid oxidation disorders -

In healthy individuals, fatty acids are broken down by the body and converted to energy. But some disorders affect this process.

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Fatty acid oxidation disorders -

These include medium-chain acyl-CoA dehydrogenase deficiency (MCAD), and trifunctional protein deficiency (TFP).

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Amino acid metabolism disorders -

These conditions occur when the baby is unable to process certain amino acids. Amino acids are the building blocks of protein.

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Amino acid metabolism disorders -

Disorders include PKU, homocystinuria, tyrosinemia, non-ketotic hyperglycinemia, and the aforementioned maple syrup urine disease.

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Organic acid metabolism disorders -

Babies with these disorders are unable to break down food properly, leading to organic acids building up in the body, mostly amino acids such as lysine and tryptophan, to name a few.

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Organic acid metabolism disorders -

Examples of disorders include 3-methylcrotonyl-CoA carboxylase deficiency (3MCC), propionic acidemia (PROP), and glutaric acidemia type 1 (GA1), among others.

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Endocrine disorders -

These disorders affect our endocrine system, more specifically the glands that produce hormones. The malfunction of these glands can lead to development and growth problems.

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Endocrine disorders -

Endocrine disorders include primary congenital hypothyroidism (CH) and congenital adrenal hyperplasia (CAH).

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Hemoglobin disorders -

Hemoglobin disorders, or hemoglobinopathies, are disorders that affect red blood cells. These are the cells responsible for transporting oxygen in the blood.

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Hemoglobin disorders -

Examples include S,S disease (sickle cell anemia) (Hb SS), S, beta-thalassemia (Hb S/ßTh), and S, C disease (Hb S/C).

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Congenital heart defects -

Critical congenital heart defects (CCHD) can affect newborns, so a pulse oximetry test is done to check the oxygen levels in the blood in the first instance. Not all heart conditions are detected by this test, however.

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Urea cycle disorders -

Some of these disorders cause ammonia to build up in the blood, which is toxic. For this reason, some newborns are screened for them.

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Hearing loss -

Hearing loss affects many newborns around the world, which can then have a great impact in how the child develops. There are different types of hearing loss, as well as different causes.

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Hearing loss -

Screening can involve tests called auditory brainstem response (also called ABR or BAER), and otoacoustic emissions (also called OAE).

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Severe combined immunodeficiency -

Some newborns are also screened for SCID. These disorders are caused by deficiency in immune cells (T-cells) and mutations in different genes, which can affect a baby’s immunity.

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Duchenne muscular dystrophy (DMD) -

Screening for DMD has been included in many newborn screening programs around the world. The condition causes muscle degeneration and weakness.

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Cystic fibrosis (CF) -

New Zealand and some regions of Australia have been screening for CF since the early 1980s. Nowadays, many European countries, as well as some US states and Canadian provinces, do so as well.

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False positives -

Newborn screening has been proven to be efficient and indeed a preventative measure that has saved many children’s lives. Though like with other areas of medicine, false positives are always a possibility. In which case, further tests are usually conducted.

Sources: (Children’s Hospital of Philadelphia) (March of Dimes) (Institute of Human Genetics)  

See also: See a doctor if your kids have these symptoms

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