DiGeorge syndrome: symptoms, causes and treatment

The symptoms of this medical disorder are varied and have to do with a chromosomal problem.

DiGeorge syndrome affects the production of lymphocytes and can cause various autoimmune diseases, among other things. It is a genetic and congenital condition that can affect 1 in 4000 births, and is sometimes detected until adulthood.

In the following we shall see what DiGeorge syndrome is and what are some of its consequences and main manifestations.

What is DiGeorge Syndrome?

DiGeorge Syndrome is an immunodeficiency disease caused by an overgrowth of certain cells and tissues during embryonic development.. It usually affects the thymus gland, and with this, and the production of T-lymphocytes, which results in the frequent development of infections.

Causes

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

Likewise, because of its signs and symptoms, it is also known as Velocardiofacial Syndrome or Abnormal Conotruncal Face Syndrome. The deletion of a fraction of chromosome 22 may be caused by random sperm- or egg-related events, and in rare cases by hereditary factors.and in a few cases by hereditary factors. So far what is known is that the causes are unspecific.

Symptoms and main characteristics

The manifestations of DiGeorge syndrome may vary according to the organism itself. For example, there are people who present severe cardiac involvement or some type of intellectual disability and even special susceptibility to psychopathological symptoms, and there are people who do not present any of these.

This symptomatic variability is referred to as phenotypic variabilitysince it depends largely on the genetic load of each person. In fact, this syndrome is considered as a clinical picture with a high phenotypic variability. Some of the most common features are the following.

1. Characteristic facial appearance

Although this does not necessarily occur in all people, some of the facial features of Digeorge syndrome include a well-developed chin, heavy lidded eyes, slightly turned back ears with part of the upper lobes above them. There may also be cleft palate or malfunction of the palate..

2. Cardiac pathologies

It is common that different alterations of the heart, and therefore of its activity, develop. Generally these alterations affect the aorta (the most important blood vessel). (the most important blood vessel) and the specific part of the heart where it develops. Sometimes these alterations may be very slight or may 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 in this process.. 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 with a small thymus produce fewer lymphocytes.

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

4. Development of autoimmune diseases

Another consequence of a lack of T-lymphocytes is that autoimmune diseases may develop. autoimmune disease may developautoimmune disease, which is when the immune system (antibodies) tends to act inappropriately towards the body itself.

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

5. Alterations in the parathyroid gland

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

Treatment

The recommended therapy for people with DiGeorge syndrome is directed towards correcting the alterations in the organs and tissues. However, due to the high phenotypic variability, the therapeutic indications may be different depending on the manifestations of each person..

For example, to treat parathyroid gland disorders, a calcium compensation treatment is recommended, and for cardiac disorders there is a specific medication or in some cases a surgical intervention is recommended. It may also happen that the T lymphocytes function normally, so that no calcium compensation treatment is required.In this case, no therapy is required for the immunodeficiency. It may also happen that the production of T-lymphocytes gradually increases with age.

In the opposite case, specific immunological care is needed, including constant monitoring of the immune system and T-lymphocyte production. For this reason, it is recommended that if a person has recurrent infections without apparent cause, tests should be performed to evaluate the entire system. Finally, in the case that the person completely lacks 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 immunologic variability in nine patients with DiGeorge syndrome. Revista Médica de Chile, 132: 26-32.
• Immune Deficiency Foundation. (2018). DiGeorge Syndrome. Retrieved June 7, 2018. Available at https://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/digeorge-syndrome.