This gene encodes an enzyme that catalyzes the hydrolysis
of adenosine to inosine. Various mutations have been described for
this gene and have been linked to human diseases. Deficiency in
this enzyme causes a form of severe combined immunodeficiency
disease (SCID), in which there is dysfunction of both B and T
lymphocytes with impaired cellular immunity and decreased
production of immunoglobulins, whereas elevated levels of this
enzyme have been associated with congenital hemolytic anemia.