ADA2 genotype and enzyme activity may predict vasculitic or hematologic DADA2 phenotype

Area of Science:

• Immunology
• Genetics
• Rheumatology

Background:

• Deficiency of adenosine deaminase 2 (DADA2) is a rare autoinflammatory disorder.
• DADA2 presents with a wide spectrum of clinical manifestations.
• Understanding the genotype-phenotype correlation is crucial for patient management.

Purpose of the Study:

• To investigate the genetics, phenotypes, and treatment outcomes in a cohort of DADA2 patients.
• To establish correlations between genetic variants, enzyme activity, and clinical presentation.
• To evaluate treatment responses and the role of hematopoietic cell transplantation (HCT).

Main Methods:

• Retrospective analysis of 48 DADA2 patients from Germany, Austria, and Switzerland.
• Assessment of hematological and immunological features.
• Correlation analysis of genetic ADA2 activity, patient ADA2 activity, and clinical phenotypes.

Main Results:

• High incidence of hematological (83%) and immunological (85%) features observed.
• Anti-tumor necrosis factor therapy showed a 58% full-response rate.
• Lower patient ADA2 activity correlated with neutropenia and HCT decision, while higher activity predicted vasculitis.
• Patients receiving HCT had significantly more genetic variants associated with low residual ADA2 activity.

Conclusions:

• ADA2 enzyme activity is a key determinant of DADA2 clinical phenotype.
• Genotype-phenotype correlations provide valuable insights for DADA2 patient management.
• Findings support the link between ADA2 activity and disease manifestations, extending in vitro observations to clinical data.