Hershfield (2006) defines adenosine deaminase (ADA) deficiency as “a systemic purine metabolic disorder that primarily affects lymphocyte development, viability, and function” (para. 1). Its clinical phenotypic spectrum is comprised of four types. The major phenotypic expression of ADA deficiency is severe combined immunodeficiency disease (SCID) is usually diagnosed during the first year of life, namely, its first half. Depending on the time of its onset combined immunodeficiency disease may be also diagnosed during the first ten years (the delayed onset) or between the ages of 20 and 40 (the adult onset) (Hershfield, 2006). Another form of ADA deficiency cells is expressed in a higher ADA activity in nuclear cells while it is rather low in erythrocytes. This phenotypic expression is recognized as partial ADA deficiency.
Symptoms and Manifestations
ADA deficiency is inherited, and it is a rare but very serious and dangerous disease. With its capacity to disable a person’s immune system leaving them vulnerable to any types of infections. The individuals with ADA deficiency tend to be exposed to various health threats on the regular basis that either eventually begins to threaten their life. As pointed out by Nyhan, Barshop, and Ozand (2005), the majority of the patients affected by ADA deficiency show the failure to thrive throughout the first months of life. Among the other symptoms typical for ADA deficiency there is chronic diarrhea that happens due to the impact of viral and bacterial infection that the body is unable to resist. The onset of the disease occurs right after the maternal antibodies disappear from the infant’s body (Nyhan et al., 2005). Apart from diarrhea, the most common health and life threats faced by the infants with ADA deficiency are extensive candidiasis, recurring pneumonia and otitis, skin infections causing lesions and rash. Overall, the infections of gastrointestinal tract, respiratory system, and skin are some of the most frequently observed manifestations of the deficiency.
Source of Disease and Diagnosing
ADA deficiency cannot be transmitted to a healthy individual. To be an ADA deficiency patient, one is to be born with it. For the deficiency to occur in an infant, both parents need to be the carriers of the disease and to pass the copies of the defective genes to the child (Adenosine deaminase (ADA) deficiency, 2016). ADA deficiency may be diagnosed at the fetal stages by means of chorionic villus sampling (collecting the sample of amniotic sac tissue) or through a test of the blood of the fetus taken from the umbilical cord (Adenosine deaminase (ADA) deficiency, 2016).
The disease is extremely dangerous and the majority of infants born with it tend not to survive longer than a few months. Currently, the science does not know any specific cure for the ADA deficiency. However, the disease is addressed with the help of measures designed to support and stimulate the immune system of the affected infants. Among such treatments there are enzyme replacement therapy (injections of ADA enzymes conducted on the regular basis to fulfill the patient’s deficiency), red blood cell transfusions with high level of adenosine deaminase, or a transplantation of bone marrow as a source of immune cells (a healthy biological donor is needed for this type of treatment). Moreover, the treatments of manifestations are available for the patients suffering from the infections due to ADA deficiency. Usually, the infections are addressed with the courses of antibiotics and the intravenous administration of immunoglobulin (Hershfield, 2006).