Question

Describe the clinical features and treatment of syndrome with deficiency of adenosine deaminase.

Hint:

Early diagnosis and treatment, particularly with bone marrow transplant or enzyme replacement therapy, are critical for improving the survival and quality of life for individuals with ADA deficiency.

Answer 1

Step 1: Overview of Adenosine Deaminase Deficiency.
Adenosine deaminase (AD deficiency is a genetic disorder that results in severe combined immunodeficiency (SCID), leading to an impaired immune system. ADA is crucial for the breakdown of purines, and its deficiency leads to toxic accumulation of adenosine and deoxyadenosine, which inhibits lymphocyte development.
Step 2: Clinical Features.
- Severe infections: Due to the compromised immune system, individuals with ADA deficiency are highly susceptible to infections, including bacterial, viral, and fungal infections.
- Failure to thrive: Infants with ADA deficiency may exhibit growth delays and developmental issues.
- Absence of T and B lymphocytes: Laboratory findings reveal a profound deficiency in both T and B lymphocytes, which results in a lack of normal immune responses.
Step 3: Treatment.
- Bone marrow transplant: The most effective treatment is a hematopoietic stem cell transplant (HSCT), which can restore the immune system.
- Enzyme replacement therapy (ERT): ADA enzyme replacement can help reduce toxic metabolites and restore partial immune function.
- Gene therapy: An emerging option for ADA deficiency is gene therapy, where the patient's own stem cells are genetically modified to express the ADA enzyme.