Adenosine Deaminase Deficiency (ADA Deficiency)
Also known as: ADA-SCID, Severe Combined Immunodeficiency due to Adenosine Deaminase Deficiency
Adenosine Deaminase Deficiency (ADA Deficiency) is a rare, inherited metabolic disorder that causes severe combined immunodeficiency (SCID). It results from a deficiency of the adenosine deaminase (ADA) enzyme, leading to the accumulation of toxic metabolites that are particularly harmful to lymphocytes. This impairs the development and function of the immune system, making affected individuals highly susceptible to severe and recurrent infections.
Imagine your body's army (immune system) is missing some important soldiers because of a broken part. ADA Deficiency is like having that broken part, so your body can't fight off germs very well, and you get sick easily. Doctors can give you medicine or a special transplant to fix it.
Signs & Symptoms
- Severe and recurrent infections (e.g., pneumonia, sepsis)
- Failure to thrive
- Chronic diarrhea
- Skin rashes
- Developmental delay
- Neurological abnormalities (in some cases)
- Skeletal abnormalities (e.g., costochondral thickening)
- Hepatosplenomegaly (enlarged liver and spleen)
Treatment Options
Enzyme Replacement Therapy (ERT) with PEG-ADA
HIGHLY EFFECTIVE Approved 1990Hematopoietic Stem Cell Transplantation (HSCT)
HIGHLY EFFECTIVEGene Therapy
HIGHLY EFFECTIVE Approved 2021Supportive Care (e.g., antibiotics, immunoglobulin replacement)
SUPPORTIVEDiagnosis
- Newborn screening (in some regions)
- Measurement of ADA enzyme activity in red blood cells
- Lymphocyte count and function tests
- Genetic testing for mutations in the ADA gene
- Assessment of immune function (e.g., immunoglobulin levels, T-cell subsets)
History
ADA Deficiency was first described in 1972 as a cause of severe combined immunodeficiency. It was one of the first genetic diseases to be treated with gene therapy, marking a significant milestone in the field of genetic medicine.
Recent Breakthroughs
FDA Approves Gene Therapy for ADA-SCID
The FDA approved Strimvelis, a gene therapy for ADA-SCID, providing a potentially curative treatment option for affected individuals. This approval marks a significant advancement in the treatment of this rare disease.