Adenosine deaminase (ADA) deficiency is a genetic disorder that affects the immune system. ADA is an enzyme that plays a critical role in the development and function of T and B lymphocytes, which are important cells in the immune system that protect the body against infections. In ADA deficiency, the lack of this enzyme leads to the accumulation of toxic substances in the body that damage lymphocytes and impair their function.
The condition can be inherited in an autosomal recessive pattern, meaning that an affected person must inherit two copies of the mutated gene (one from each parent) to develop the disorder. People with ADA deficiency are susceptible to recurrent and severe infections, especially in the lungs, ears, and sinuses. They may also have other health problems, including developmental delays, neurological problems, and autoimmune disorders.
Treatment for ADA deficiency usually involves enzyme replacement therapy, in which the missing enzyme is replaced with regular injections. This can help restore immune function and prevent infections. In severe cases, bone marrow or stem cell transplants may be necessary to replace the defective immune cells. Genetic counseling may also be recommended for affected individuals and their families.