Adenosine deaminase (ADA) deficiency is a rare genetic disorder that affects the immune system. It is caused by mutations in the gene that provides instructions for making the ADA enzyme, resulting in reduced or absent ADA activity in the body.
The ADA enzyme is important for the normal development and function of white blood cells, which play a crucial role in fighting infections. Without adequate ADA activity, toxic byproducts of metabolism accumulate within white blood cells, leading to their destruction and impairing the immune system’s ability to function properly.
The most severe form of ADA deficiency is known as severe combined immunodeficiency (SCID), which is characterized by a near-complete absence of functional white blood cells. Infants with SCID are highly susceptible to life-threatening infections and often die within the first few months of life unless they receive aggressive medical intervention, such as a bone marrow transplant.
Less severe forms of ADA deficiency can cause chronic infections, recurrent respiratory infections, failure to thrive, and developmental delays. Some affected individuals may also develop autoimmune disorders, which occur when the immune system attacks the body’s own tissues and organs.
Diagnosis of ADA deficiency is typically made through blood tests that measure ADA enzyme activity or genetic testing to identify mutations in the ADA gene. Treatment options include enzyme replacement therapy, in which purified ADA enzyme is administered to the patient, or hematopoietic stem cell transplantation, in which the patient’s bone marrow is replaced with donor bone marrow that produces functional ADA enzyme.
In summary, ADA deficiency is a rare genetic disorder that affects the immune system, leading to a range of symptoms including severe combined immunodeficiency (SCID) and chronic infections. Diagnosis is typically made through blood tests or genetic testing, and treatment options include enzyme replacement therapy and bone marrow transplantation.
