DiGeorge syndrome: symptoms, causes and treatment

DiGeorge Syndrome affects lymphocyte production and can cause various autoimmune diseases, among other things. It is a genetic and congenital condition that can affect 1 in 4,000 births, and is sometimes detected until adulthood.

Next we will see what is DiGeorge syndrome and what are some of its consequences and main manifestations.

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What is DiGeorge Syndrome?

DiGeorge Syndrome is an immunodeficiency disease caused by an overgrowth of certain cells and tissues during embryonic development. It generally affects the thymus gland, and with this, and the production of T lymphocytes, which has as a consequence the frequent development of infections.

Causes

One of the main characteristics that 90% of people diagnosed with this syndrome present is that a small part of chromosome 22 is missing (from position 22q11.2, specifically). For this reason, Digeorge Syndrome is also known as chromosome 22q11.2 deletion syndrome.

Likewise, and due to its signs and symptoms, it is also known as Velocardiofacial Syndrome or Abnormal Conotruncal Face Syndrome. Deletion of a fraction of chromosome 22

can be caused by random episodes related to sperm or eggs, and in few cases by hereditary factors. So far what is known is that the causes are nonspecific.

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Symptoms and main characteristics

The manifestations of DiGeorge Syndrome can vary according to the body itself. For example, there are people who have severe heart disease or some type of intellectual disability and even special susceptibility to psychopathological symptoms, and there are people who do not present any this.

This symptomatic variability is known as phenotypic variability., since it depends to a great extent on the genetic load of each person. In fact, this syndrome is considered a clinical picture with high phenotypic variability. Some of the most common features are as follows.

1. Characteristic facial appearance

Although this does not necessarily occur in all people, some of the facial features of Digeorge Syndrome include a highly developed chin, eyes with heavy eyelids, ears slightly turned back with part of the upper lobes above they. There may also be a cleft palate or poor palate function.

2. Cardiac pathologies

It is common for different alterations of the heart to develop, and therefore of its activity. These alterations generally affect the aorta (the most important blood vessel) and the specific part of the heart where it develops. Sometimes these alterations can be very mild or they can be absent.

3. Alterations in the thymus gland

In order to act as a protector against pathogens, the lymphatic system must produce T cells. In this process, the thymus gland plays a very important role. This gland begins its development in the first three months of fetal growth, and the size it reaches directly affects the number of T-type lymphocytes that develop. People who have a small thymus make fewer lymphocytes.

While lymphocytes are essential for protection against viruses and for producing antibodies, lymphocytes People with DiGeorge Syndrome have a significant susceptibility to viral, fungal and bacterial. In some patients, the thymus gland may even be absent, requiring immediate medical attention.

4. Development of autoimmune diseases

Another consequence of the lack of T lymphocytes is that you can develop an autoimmune disease, which is when the immune system (antibodies) tends to act inappropriately towards the body itself.

Some of the autoimmune diseases caused from DiGeorge Syndrome are idiopathic thrombocytopenic purpura (which attacks platelets), autoimmune hemolytic anemia (against red blood cells), rheumatoid arthritis or autoimmune disease of the thyroid.

5. Alterations in the parathyroid gland

DiGeorge syndrome too can affect the development of a gland called the parathyroid gland (It is located in the front of the neck, near the thyroid). This can cause changes in metabolism and alterations in calcium levels in the blood, which can lead to seizures. However, this effect tends to become less severe as time passes.

Treatment

The therapy recommended for people with DiGeorge Syndrome is aimed at correcting the abnormalities in the organs and tissues. However, and due to the high phenotypic variability, therapeutic indications may be different according to the manifestations of each person.

For example, to treat alterations of the parathyroid gland, a calcium compensation treatment is recommended, and for cardiac alterations there is a specific medication or in some cases an intervention is recommended surgical It can also happen that T lymphocytes work normallyTherefore, no therapy for immunodeficiency is required. Likewise, it may happen that the production of T lymphocytes gradually increases with age.

In the opposite case, specific immunological attention is needed, which includes constantly monitoring the immune system and the production of T lymphocytes. For this reason, it is recommended that if a person has recurrent infections without an apparent cause, tests are carried out to evaluate the entire system. Finally, in the event that the person is completely devoid of T cells (which can be called “complete DiGeorge syndrome”), a thymus transplant is recommended.

Bibliographic references:

• Aglony, M., Lizama, M, Méndez, C. et al. (2004). Clinical manifestations and immunological variability in nine patients with DiGeorge Syndrome. Medical Journal of Chile, 132: 26-32.
• Immune Deficiency Foundation. (2018). DiGeorge Syndrome. Retrieved June 7, 2018. Available in https://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/digeorge-syndrome.