Prospective Observational Study Evaluating the Prevalence of Adenosine Deaminase (ADA) Enzyme Deficiency Disease in Patients With Lymphopenia and/or Immunoglobulin E Elevation in Adult Immunology and Hematology Clinics

Primary immunodeficiencies are encountered with signs and symptoms related to various disciplines of medicine and are detected more often in our country than in other societies.

Severe Combined Immunodeficiencies (SCID) are a heterogeneous group of diseases caused by hereditary errors in genes involved in the development and/or function of T, B, and sometimes NK cells, which cause serious dysfunction of the immune system. The incidence is estimated at 1/100,000 live births in the USA. Although the exact incidence of inbreeding is not known in our country, where inbreeding is common, it is expected that those who show autosomal recessive transition will be more common, especially. Each step that is effective in the emergence of an immune response creates the potential for a primary immunodeficiency disease. Due to the development of molecular and cellular techniques, the possibility of prenatal diagnosis has arisen with the detection of localization and mutations of the defective gene in various immunodeficiencies. The recognition of these disorders by clinicians is important for reducing long-term complications due to recurrent infections and preventing mortality with appropriate treatment.

The frequency of SCID in our country is unknown. Unlike in Europe and America, SCID types, which are autosomal recessive in our country, are considered to be the most common form due to the high rates of inbreeding. The figure obtained by comparing the number of live babies born in a year in Konya with the number of SCID cases diagnosed in the same year at the Pediatric Immunology Clinic of the Meram Faculty of Medicine of Selcuk University, the only primary immunodeficiency diagnostic center in the region, is 1/10,000. This preliminary study shows that in our country this disease is much more common than in Europe and America. About 1,300 a year in our country.considering that 000 babies have been born, it should be expected that 140 new cases of SCID should be encountered every year. The number of cases diagnosed in our country is much lower than this figure.

To date, more than 20 genetic defects have been identified that cause SCID. All known genetic defects disrupt the development of cells of the immune system, causing combined immunodeficiency. One of them, the ADA defect, is also a metabolic disease, due to which there is a lack of enzymes.

ADA catalyzes the deamination of purine nucleosides adenosine (Ado) and 2'-deoxyadenosine (dAdo), which are produced during the degradation and transformation of RNA and DNA. ADA is a cleansing enzyme; it detoxifies purines. In ADA deficiency, 2'-deoxyadenosine (dAdo) is phosphorylated and converted into deoxyadenosine triphosphate (dATP). Accumulation of DATP disrupts DNA repair and replication. In ADA deficiency, a high percentage of dATP accumulates, especially in erythrocytes and lymphocytes. Increased levels of adenosine break down the wall of the lymphocyte. It inhibits the development of lymphocytes in the thymus. A kind of lymphocyte intoxication occurs. It leads to a severe form of lymphopenia. Approximately 10-20% of AKIS are diagnosed as ADA enzyme deficiency. It shows an autosomal recessive transition. Your gene is 20. it is localized on the long arm of the chromosome.