deficiency of adenosine deaminase 2

Adenosine deaminase 2 deficiency

Deficiency of Adenosine deaminase 2 (DADA2) is a monogenic disease associated with systemic inflammation and vasculopathy that affects a wide variety of organs in different patients. As a result, it is hard to characterize a patient with this disorder. Manifestations of the disease include but are not limited to recurrent fever, livedoid rash (reticularis or racemosa), various cytopenias, stroke, immunodeficiency, and bone marrow failure. Symptoms often onset during early childhood, but some cases have been discovered as late as 65 years old. DADA2 is caused by mutations in the ADA2 gene, and is inherited in an autosomal recessive manner. The protein product of this gene, adenosine deaminase 2 (ADA2), is an extracellular enzyme that breaks down adenosine and may also serve as a growth factor. Pathogenic mutations decrease this enzymatic activity in patient blood, leading to disease manifestations. However, mutational status and residual enzyme activity levels do not explicitly correlate with the type of disease a patient displays. The most common treatment for DADA2 is TNF inhibitors. This therapy tends to prevent vasculitis-related manifestations such as rash and stroke, but does not perform well in individuals presenting with severe hematologic and immunologic abnormalities such as bone marrow failure or severe recurrent infections. In these cases, hematopoietic stem cell transplantation has led to major improvements in the vascular, hematologic, and immunologic manifestations of disease.