GENE REFERENCE / HGNC:186

ADA

adenosine deaminase

protein-coding gene20q13.12Gene information

What does this gene do?

The ADA gene provides instructions for producing the enzyme adenosine deaminase. This enzyme is produced in all cells, but the highest levels of adenosine deaminase are found in immune system cells called lymphocytes. These cells defend the body against foreign invaders, such as viruses or bacteria. Lymphocytes are produced in specialized lymphoid tissues throughout the body, including in a gland located behind the breastbone called the thymus and in the lymph nodes.

The function of the adenosine deaminase enzyme is to get rid of a molecule called deoxyadenosine, which is generated when DNA is broken down. A buildup of deoxyadenosine in cells can lead to early cell death. Adenosine deaminase converts deoxyadenosine to another molecule called deoxyinosine, which is not harmful.

Source: MedlinePlus, National Library of Medicine. Source publication: 2024-05-21. Source review: 2024-05.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiencyMONDO:0007064 · Evaluated 2020-11-19	Autosomal recessive	DefinitiveSCID-CID Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 802
Submissions for variants in or overlapping this gene: 1,593
Submissions explicitly reporting this gene: 1,565
Alleles reported pathogenic / likely pathogenic: 196
VariationIDs with uncertain significance: 193
VariationIDs with conflicting classifications: 14

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about ADA?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 196 alleles in ADA reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in ADA.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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