Metabolic diseases in newborns

At birth, newborn screening is one of the first medical evaluations performed to detect the presence of different types of diseases, including metabolic diseases in newborns. Although these diseases are not very common, identifying them is really important because it can prevent the onset of serious symptoms, which has a positive impact on the child’s health.

What are congenital metabolic diseases?

Inborn errors of metabolism are biochemical disorders caused by genetic alterations that specifically affect a protein or enzyme involved in a metabolic process. These conditions can interfere with vital processes such as the breakdown of food for energy, the elimination of wastes or the production of enzymes necessary for the proper functioning of the body. Some examples of these diseases are:

• Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency: Affects the body’s ability to break down certain fats and convert them into energy. It can lead to fatigue, severe tiredness, liver disease, among others. Part of its treatment is to follow a diet low in fat and rich in carbohydrates, in addition to avoiding long periods of fasting.

• Phenylketonuria: It consists of the accumulation of phenylalanine in the body, due to a deficit or absence of the enzyme responsible for its degradation or metabolism. Phenylalanine is one of the 9 essential amino acids for the organism, and it is supplied through the diet by means of foods containing proteins or aspartame, a sweetener. The accumulation of this amino acid can cause convulsions, growth problems, skin rashes, among others. Its treatment consists of a protein-restricted diet based on special milks and vegetables.

• Galactosemia: It is a deficiency of the enzymes that degrade galactose, so it accumulates in the organism becoming a toxic metabolite. Signs and symptoms are hepatic and renal dysfunction, cognitive deficit, cataracts, among others. Its treatment is the dietary restriction of dairy products, since they contain lactose which, when metabolized, gives rise to galactose.

Frequency and carrier rate

Although metabolic diseases are considered rare in isolation, their impact can be significant. The frequency of these diseases varies by population and geographic region, but taken together they affect a significant percentage of neonates. For example, in general, phenylketonuria and MCAD deficiency affect 1 in 10,000 neonates and galactosemia affects 1 in 77,000.

It is essential to remember that many of these diseases are hereditary, in these cases generally both parents are asymptomatic carriers of the disease and transmit the damaged copy of the gene to their offspring, causing the disease.

In the case of galactosemia, it is estimated that approximately 1 in 64-108 people of European descent carry a variant in the gene responsible for the disease, while for phenylketonuria it is estimated that this occurs in 1 in 50 people. These values indicate that the gene alteration can be transmitted to their children without necessarily manifesting the disease themselves. That is why screening and early detection are of vital importance.

Screening for metabolic diseases in neonates

The heel prick test is often the most common approach to newborn screening. This tool is essential in the early detection of metabolic and genetic diseases in newborns. The test is performed within the first 24 to 48 hours of life with a blood sample from the infant’s heel which is then analyzed.

On the other hand, genetic tests allow the analysis of a greater number of diseases from a blood or saliva sample, in order to identify alterations that may cause a metabolic disease. In addition to the number of diseases that can be revealed by these studies, another advantage of the use of genetic tests is their high yield compared to biochemical tests.

Early detection of metabolic diseases in neonates is crucial to providing the baby with a healthy life. When these conditions are detected in a timely manner, specific treatments can be initiated that can prevent the development of severe symptoms and improve the infant’s quality of life. In the case of several metabolic disorders, a proper diet can prevent the onset of severe symptoms.

At Veritas we are interested in providing tools that allow patients to improve their health. We have key neonatal screening options for the detection of metabolic and genetic diseases that may appear in the early stages of life.