Adenosine deaminase deficiency
Adenosine deaminase (ADA) deficiency is a genetic disorder characterized by a lack of the enzyme adenosine deaminase, which is essential for the normal functioning of the immune system. ADA deficiency is an autosomal recessive disorder, meaning that an individual must inherit two defective copies of the ADA gene (one from each parent) to develop the condition.
ADA deficiency results in the accumulation of toxic byproducts, such as adenosine and deoxyadenosine, within immune cells, particularly lymphocytes (a type of white blood cell). This buildup of toxic metabolites disrupts the development and function of lymphocytes, leading to severe combined immunodeficiency (SCID), also known as “ADA-SCID.”
SCID is a life-threatening condition characterized by a severely compromised immune system, leaving affected individuals highly susceptible to recurrent and severe infections from a wide range of pathogens, including bacteria, viruses, and fungi. Without treatment, these infections can be fatal in infancy or early childhood.
Symptoms of ADA-SCID typically present within the first few months of life and may include:
- Failure to thrive
- Chronic diarrhea
- Recurrent respiratory infections
- Persistent oral thrush (yeast infection)
- Failure to gain weight
- Developmental delays
- Failure to grow
Early diagnosis and prompt treatment are crucial for individuals with ADA deficiency. Treatment options may include enzyme replacement therapy (administering synthetic ADA enzyme), hematopoietic stem cell transplantation (bone marrow or stem cell transplant), or gene therapy (introducing a functional ADA gene into the patient’s cells).
Advances in early detection and treatment have improved outcomes for individuals with ADA deficiency, but ongoing medical management and lifelong monitoring are typically necessary to manage the condition effectively and prevent complications.