National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Adenosine deaminase deficiency


Other Names:
ADA deficiency; Severe combined immunodeficiency due to adenosine deaminase deficiency; Severe combined immunodeficiency due to ADA deficiency; ADA deficiency; Severe combined immunodeficiency due to adenosine deaminase deficiency; Severe combined immunodeficiency due to ADA deficiency; SCID due to ADA deficiency; Severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency; ADA-SCID; Adenosine deaminase deficient severe combined immunodeficiency See More
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Adenosine deaminase deficiency (ADA deficiency) is an inherited condition that damages the immune system and is a common cause of severe combined immunodeficiency (SCID). People with SCID due to ADA deficiency are unable to fight off most types of infections, including bacterial, viral and fungal infections. Most people with ADA deficiency develop symptoms before 6 months of age. The earliest symptoms of ADA deficiency include pneumonia, chronic diarrhea, widespread skin rashes, slowed growth, and/or developmental delay. Some people with ADA deficiency will develop symptoms later in life. The symptoms in the late-onset form are typically milder than in the form that occurs in infancy. ADA deficiency is caused by mutations in the ADA gene and is inherited in an autosomal recessive manner.[1][2] Diagnosis may be suspected by newborn screening or symptoms and confirmed by blood and genetic test results.  Currently, the most effective treatment is transplantation of blood-forming stem cells from the bone marrow of a healthy brother or sister of the person with ADA deficiency.[2][3]
Last updated: 11/28/2018
The symptoms of adenosine deaminase deficiency (ADA deficiency) usually begin before 6 months of age.[1][2] Babies with ADA deficiency usually develop serious lung infections and chronic diarrhea. They have trouble gaining weight and do not grow very well. Other symptoms include skin rashes, absent tonsils and lymph nodes, bone abnormalities, and developmental delay.[2][4] Approximately 10-15% of people with ADA deficiency do not develop symptoms until  later in childhood, often between ages 1 and 10, or even into adulthood. In these cases, people are usually diagnosed with "combined immunodeficiency (CID)", since symptoms are initially milder than those seen in SCID. However, over time, people with the milder form of ADA deficiency may develop chronic lung damage, malnutrition, and other health problems.[1][2]

There are some people who have partial ADA deficiency. People with this condition have low amount of ADA enzyme in some cells, but have normal immune systems. Partial ADA deficiency is considered a benign condition that does not cause health problems.[2]

Last updated: 11/28/2018

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
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HPO ID
30%-79% of people have these symptoms
Absence of lymph node germinal center 0002849
Absent tonsils 0030813
Allergy 0012393
Anti-thyroid peroxidase antibody positivity 0025379
B lymphocytopenia
Low B cell count
0010976
Decrease in T cell count
Low T cell count
Reduced number of T cells
[ more ] 		0005403
Diarrhea
Watery stool
0002014
Failure to thrive
Faltering weight
Weight faltering
[ more ] 		0001508
Increased circulating IgE level 0003212
Inflammatory abnormality of the skin
Skin inflammation
0011123
Lack of T cell function 0005354
Pulmonary insufficiency 0010444
Recurrent opportunistic infections 0005390
Recurrent otitis media
Recurrent middle ear infection
0000403
Recurrent pneumonia 0006532
Recurrent upper respiratory tract infections
Recurrent colds
0002788
Sinusitis
Sinus inflammation
0000246
Percent of people who have these symptoms is not available through HPO
Abnormality of pelvic girdle bone morphology
Abnormal shape of pelvic girdle bone
0002644
Absent specific antibody response 0005424
Anterior rib cupping 0000907
Aplasia of the thymus
Absent thymus
0005359
Asthma 0002099
Autoimmune hemolytic anemia 0001890
Autoimmune thrombocytopenia 0001973
Autosomal recessive inheritance 0000007
B-cell lymphoma 0012191
Decreased circulating IgA level 0002720
Decreased circulating IgG2 level 0008348
Decreased circulating total IgM 0002850
Diffuse mesangial sclerosis 0001967
Eosinophilia
High blood eosinophil count
0001880
Growth arrest lines 0031164
Hepatomegaly
Enlarged liver
0002240
Platyspondyly
Flattened vertebrae
0000926
Pneumonia 0002090
Recurrent bacterial infections
Bacterial infections, recurrent
Frequent bacterial infections
Increased susceptibility to bacterial infections
Recurrent major bacterial infections
[ more ] 		0002718
Recurrent fungal infections 0002841
Recurrent viral infections 0004429
Reduced red cell adenosine deaminase level 0030273
Severe B lymphocytopenia 0005365
Severe combined immunodeficiency 0004430
Somatic mosaicism 0001442
Splenomegaly
Increased spleen size
0001744
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Last updated: 7/1/2020
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.[1][2][4]
Last updated: 11/28/2018
Adenosine deaminase deficiency (ADA deficiency) is inherited in an autosomal recessive manner.[1][2] 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: 11/28/2018
Most states in the United States screen newborns for severe combined immune deficiency (SCID).[2][4] 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.[2][4]  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.[2]
 
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.[2][4]

Last updated: 11/28/2018

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Newborn Screening

  • An ACTion (ACT) sheet is available for this condition that describes the short-term actions a health professional should follow when an infant has a positive newborn screening result. ACT sheets were developed by experts in collaboration with the American College of Medical Genetics.
  • Baby's First Test is the nation's newborn screening education center for families and providers. This site provides information and resources about screening at the local, state, and national levels and serves as the Clearinghouse for newborn screening information.
  • US National Newborn Screening Status Report (NNSGRC) provides information and resources in the area of newborn screening and genetics to benefit health professionals, the public health community, consumers and government officials.
  • The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.
The treatment of severe combined immune deficiency due to adenosine deaminase deficiency (ADA deficiency) may include the following:[3][5]

• 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.[5] 

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.[3][5][6]

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 [7], but is still considered experimental in the US.

Last updated: 11/28/2018

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

  • Pegademase bovine (Brand name: Adagen) - Manufactured by Lediant Biosciences
    FDA-approved indication: March 1990, pegademase bovine (Adagen) was approved for enzyme replacement therapy for ADA deficiency in patients with severe combined immunodeficiency.
    National Library of Medicine Drug Information Portal
  • Elapegademase-lvlr (Brand name: Revcovi) - Manufactured by Leadiant Biosciences, Inc.
    FDA-approved indication: October 2018, elapegademase-lvlr (Revcovi) was approved for the treatment of Adenosine Deaminase-Severe Combined Immunodeficiency (ADA-SCID).
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.[5][6] Newborn screening for SCID has made it possible for more babies to get diagnosed and treated earlier.[2] 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.[3][5][6] 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.[6] People with ADA deficiency who are treated with enzyme replacement therapy (ERT) generally do well, but ERT may lose effectiveness over many years.[5] 

Without early diagnosis and treatment, babies with ADA deficiency usually do not survive past age 2.[1][2]

Last updated: 11/28/2018
Adenosine deaminase deficiency (ADA deficiency) affects about 1 in 200,000 – 1 in 1,000,000 people worldwide.[2] About 15% of all cases of severe combined immune deficiency are caused by ADA deficiency.[1]
Last updated: 11/28/2018

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes all forms of SCID.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Adenosine deaminase deficiency. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The American Society of Gene & Cell Therapy provides information on the treatment of immunodeficiency diseases.
  • Genetics Home Reference (GHR) contains information on Adenosine deaminase deficiency. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Human Genome Research Institute's (NHGRI) website has an information page on this topic. NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
  • The Screening, Technology And Research in Genetics (STAR-G) Project has a fact sheet on this condition, which was written specifically for families that have received a diagnosis as a result of newborn screening. This fact sheet provides general information about the condition and answers questions that are of particular concern to parents.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Adenosine deaminase deficiency. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Adenosine deaminase deficiency. Genetics Home Reference. July 2013; http://ghr.nlm.nih.gov/condition/adenosine-deaminase-deficiency.
  2. Hershfield M. Adenosine Deaminase Deficiency. GeneReviews. Mar 2017; http://www.ncbi.nlm.nih.gov/books/NBK1483.
  3. 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. https://www.ncbi.nlm.nih.gov/pubmed/30194989.
  4. Rubinstein A. Adenosine deaminase deficiency: Pathogenesis, clinical manifestations, and diagnosis. UpToDate. Nov 2016; https://www.uptodate.com/contents/adenosine-deaminase-deficiency-pathogenesis-clinical-manifestations-and-diagnosis.
  5. Rubinstein A. Adenosine deaminase deficiency: Treatment. UpToDate. August 2017; https://www.uptodate.com/contents/adenosine-deaminase-deficiency-treatment.
  6. 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. https://www.ncbi.nlm.nih.gov/pubmed/28748310.
  7. Aiuti A, Roncarolo MG, Naldini L. Gene therapy for ADA-SCID, the first marketing approval of an ex vivo gene therapy in Europe: paving the road for the next generation of advanced therapy medicinal products. EMBO Molecular Med. 2017; 9(6):737-740. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452047.