Immune system consists of a vast network of organs, tissues, cells, and proteins that work together to defend the body against foreign objects such as bacteria, viruses, fungi, parasites, etc. Immune cells originate from stem cells, often in the bone marrow, and develop into several types including B-lymphocytes, T-lymphocytes, NK and phagocytes. These cells and their proteins are scattered throughout the body so that they can respond quickly.
A hereditary disease affects the immune system characterized by severe malfunctions in the production of the immune T-cells and B-cells or in its functions and in some cases, there is a malfunction in the production of NK.
A defect in one of the genes responsible for the formation of the immune system.
Often symptoms manifest during the first months of life and includes recurrent bacterial, viral and fungal infections. The infection is often opportunistic, that it is caused by weak types of bacteria, fungus and viruses which normally do not affect normal people. This infection affects various areas and organs of the body, such as chest infections, fungal infections of the mouth, severe chronic diarrhea, and leads to severe growth deficiencies.
The incidence of cancers and autoimmune diseases in these patients is high because of malfunction of the immune system
Immunological analysis is based on an assessment of the capabilities of the immune system in terms of quality and quantity. The number of T-, B- and NK- lymphocytes is estimated, and the level of immunoglobulins, the antibodies produced by B- cells, is assessed, as well as the function of the T- cells. Genetic tests are then performed to determine the type of genetic mutation that causes the disease, if possible.
If the genetic mutation is determined and the parents wish to have a child in the future, it is possible to conduct a test called “Preimplantation Genetics Screening” (PGS), which is an advanced method that relies on in vitro fertilization technique. In the process, the fertilized egg is examined in the laboratory and then planted in the uterus if it is found free from hereditary disease.
In case diagnosis is confirmed, the following should be followed:
Available treatment methods:
How the disease is inherited?
The human body consists of billions of cells that make up the various organs of the body. The cells contain the DNA, which in turn carries the genes, which are responsible for the production of proteins that specify path of the composition and different functions of the body. These genes are aligned in the chromosomes.
Different genes are exposed to mutations (changes) in their composition. Some of these mutations are harmless (do not cause a malfunction of the gene and therefore the protein is normal). Other mutations, however, cause damage to the gene, which may lead to the inability to produce protein totally or partially, or to the production of abnormal protein which is unable to perform its normal function and thus produces disease with symptoms associated with the functions of the damaged gene.
How Severe combined immunodeficiency is inherited?
Most types of this disease are inherited by recessive genetics (inheritance) and there is one type inherited by sex-linked recessive inheritance.
1. Recessive heredity
2. Sex- linked recessive inheritance