Adenosine deaminase deficiency

What causes adenosine deaminase deficiency?

Adenosine deaminase deficiency (ADA deficiency) is caused by changes (mutations) in the ADA gene. This gene is responsible for making an enzyme that is found in specialized white blood cells (lymphocytes). Lymphocytes are an important part of the immune system and help protect the body from infections. The function of the ADA enzyme is to convert a substance that is harmful to lymphocytes (called deoxyadenosine) to a non-harmful substance. Mutations in the ADA gene lead to a non-working or poorly working ADA enzyme. This causes deoxyadenosine to buildup in the lymphocytes. Because of this build up, lymphocytes are unable to grow and fight infection, leading to severe combined immunodeficiency.

Last updated on 05-01-20

How is adenosine deaminase deficiency diagnosed?

Most states in the United States screen newborns for severe combined immune deficiency (SCID). One common cause of SCID is adenosine deaminase deficiency (ADA deficiency). If a newborn screen result is abnormal for SCID, additional blood tests are necessary to confirm the diagnosis of ADA deficiency (and other less common causes for SCID). These blood tests include testing for levels of immunoglobulins and white blood cells (WBCs) including T cells, B cells and natural killer cells. Immunoglobulins and WBCs are important parts of the body’s immune system. Genetic testing to identify mutations in the ADA gene may be used to confirm the diagnosis.

In children and adults with the mild form of ADA deficiency, the diagnosis is made based on symptoms which include frequent unusual infections, low WBCs in the blood, absent tonsils or lymph nodes, and low levels of the adenosine deaminase enzyme. Genetic testing for mutations in the ADA gene can confirm the diagnosis of the mild form of ADA deficiency.

Last updated on 05-01-20

How is adenosine deaminase deficiency inherited?

Adenosine deaminase deficiency (ADA deficiency) is inherited in an autosomal recessive manner. This means that to have symptoms of ADA deficiency a person must have a mutation in both copies of the responsible gene in each cell. The parents of a child with ADA deficiency usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) chance to have the condition, a 50% (1 in 2) chance to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.

Last updated on 05-01-20

What is the long-term outlook for people with adenosine deaminase deficiency?

The long-term outlook (prognosis) for people with adenosine deaminase deficiency (ADA deficiency) varies depending on the severity of the condition, the timing of the diagnosis, and the response to treatment. Newborn screening for SCID has made it possible for more babies to get diagnosed and treated earlier. This may change long-term outcomes.

For babies diagnosed early and treated with a bone marrow transplant/stem cell transplant, the long-term outlook is generally good. At this time, it isn’t clear if these children will still develop developmental or behavioral problems later in life. People with ADA deficiency who have been treated with gene therapy also seem to have a good long-term outlook, although information is still being collected. People with ADA deficiency who are treated with enzyme replacement therapy (ERT) generally do well, but ERT may lose effectiveness over many years.

Without early diagnosis and treatment, babies with ADA deficiency usually do not survive past age 2.

Last updated on 05-01-20

How many people have adenosine deaminase deficiency?

Adenosine deaminase deficiency (ADA deficiency) affects about 1 in 200,000 – 1 in 1,000,000 people worldwide. About 15% of all cases of severe combined immune deficiency are caused by ADA deficiency.

Last updated on 05-01-20

How might adenosine deaminase deficiency be treated?

The treatment of severe combined immune deficiency due to adenosine deaminase deficiency (ADA deficiency) may include the following:

• Early diagnosis and treatment of bacterial, viral, and fungal infections
• Preventative medications for certain types of pneumonia
• Intravenous (IV) immunoglobulin to boost the body's natural response to infections
• Bone marrow or stem cell transplant
• Gene therapy

The primary treatment is transplantation of blood-forming stem cells from the bone marrow of a healthy brother or sister (allogenic bone marrow transplant /stem cell transplant or BMT/SCT). This therapy is effective in approximately 70% or more of people with severe combined immunodeficiency (SCID), including SCID caused by ADA deficiency.

If a BMT/SCT is not an option, enzyme replacement therapy (ERT) may be recommended. ERT is a treatment that replaces the enzyme that is missing or not working properly (adenosine deaminase) with a bovine form of the enzyme that has been genetically modified to work in humans.

Gene therapy is also available through clinical trials, and appears to be successful in treating people with SCID due to ADA deficiency. Gene therapy involves replacing a copy of the non-working ADA gene with a working copy, so that a person can make the ADA enzyme on his or her own. Gene therapy for SCID due to ADA deficiency has been approved in Europe , but is still considered experimental in the US.

Last updated on 05-01-20

Name: Jeffrey Modell Foundation JMF 780 Third Ave
New York, NY, 10017, United States
Fax : 212-764-4180 Email: Url: JMF is a global patient organization devoted to early and precise diagnosis, meaningful treatments, and ultimately, cures - through clinical and basic research, physician education, patient support, advocacy, public awareness and newborn screening.
Name: International Patient Organization for Primary Immunodeficiencies IPOPI Rock Bottom, Trerieve Downderry
PL11 3LY
United Kingdom
Phone: 44-01503-250-668/961 Email: Url:
Name: Immune Deficiency Foundation 110 West Road, Suite 300
Towson, MD, 21204, United States
Toll Free: 1-800-296-4433 Fax : +1-410-321-9165 Email: Url:
Name: United States Immunodeficiency Network (USIDNET) 110 West Road, Suite 300
Towson, MD, 21204-4803, United States
Phone: 443-632-2558 Toll Free: 800-296-4433 (se habla español) Email: Url:
Name: Canadian Immunodeficiencies Patient Organization (CIPO) 25 La Grave St Winnepeg, MB
R3V 1J1, Canada
Phone: 877-262-2476 (toll-free) Fax : 866-942-7651 (toll-free) Email: Url:
Name: Immune Deficiencies Foundation Australia PO Box 969 Penrith NSW 2751
Phone: 800-100-198 Email: Url:
Name: Primary Immune Deficiency UK PID UK PO Box 6970
Basingstoke, RG24 4XL, United Kingdom
Toll Free: 0800 987 8986 Email: Url:
Kohn DB, Hershfield MS, Puck JM, Aiuti A et al. Consensus approach for the management of severe combined immune deficiency caused by adenosine deaminase deficiency J Allergy Clin Immunol. Sept 2018; available on-line. Reference Link Scott O, Kim VH-D, Reid B, Pham-Huy A, Atkinson A, Aiuti A, Grunebaum E. Long-term outcome of Adenosine deaminase-deficient patients – a single-center experience J Clin Immunol. 2017; 37. 582-591. Reference Link

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Drug Name Generic Name
Revcovi elapegademase-lvlr

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