Adenosine deaminase deficiency

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Adenosine deaminase deficiency, also called ADA deficiency or ADA-SCID,^[1] is an autosomal recessive^[2] metabolic disorder that causes immunodeficiency.

It accounts for about 15% of all cases of severe combined immunodeficiency (SCID).^[3]

ADA deficiency may present in infancy, childhood, adolescense, or adulthood.^[1] Age of onset and severity is related to some 29 known genotypes associated with the disorder.^[4]

Pathophysiology

Adenosine deaminase deficiency has an autosomal recessive pattern of inheritance.

ADA deficiency is due to a lack of the enzyme adenosine deaminase coded for by a gene on chromosome 20. There is an accumulation of deoxyadenosine,^[5] which causes an increase in S-adenosylhomocysteine; both substances are toxic to immature lymphocytes, which thus fail to mature. As a result, the immune system is severely compromised or completely lacking.

The enzyme adenosine deaminase is important in the purine salvage pathway.

Treatment

Treatments include:

• bone marrow transplant
• gene therapy
• ADA enzyme in PEG vehicle

On September 14, 1990,the first gene therapy to combat this disease was performed by Dr. W. French Anderson on a four year old girl, Ashanti DeSilva, at the National Institutes of Health, Bethesda, Maryland, U.S.A.^[6]

References

External links

• Adenosine deaminase deficiency - Genetics Home Reference
• Gene Therapy Net

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