Diverse Phenotypic Expressions of ADA2 Deficiency: Two Case Studies

Area of Science:

• Genetics and Molecular Biology
• Immunology
• Neurology

Background:

• Adenosine deaminase 2 (ADA2) deficiency is a rare autosomal recessive disorder.
• Its clinical spectrum has expanded beyond vasculitis to include bone marrow failure and immunodeficiency.

Purpose of the Study:

• To describe two cases of ADA2 deficiency with distinct presentations.
• To highlight the progressive nature of the disease and its implications for treatment.

Main Methods:

• Case report of two patients with ADA2 deficiency.
• Genetic analysis confirming pathogenic ADA2 variants.
• Clinical observation of disease progression and treatment response.

Main Results:

• Patient 1 presented with early-onset stroke mimicking polyarteritis nodosa (PAN).
• Patient 2 exhibited adult-onset vasculitis progressing to neutropenia, infection, and lymphoproliferation.
• This case demonstrated disease progression from vasculitis to bone marrow failure.

Conclusions:

• ADA2 deficiency is a dynamic disease with evolving manifestations.
• Current treatment guidelines may need revision, considering early hematopoietic stem cell transplantation (HSCT).
• Physicians must recognize the varied presentation and multi-organ involvement for timely intervention.