Early onset is an indication of the severity of DADA2 disease.

Objective: To find indicators of disease severity and factors of early remission in patients with deficiency of adenosine deaminase 2 (DADA2).

Methods: We enrolled six DADA2 patients from six families. Direct sequencing of adenosine deaminase 2 gene (ADA2) was performed by Sanger analysis. A literature review was conducted for articles regarding paediatric DADA2.

Results: We found that more organs were involved in early-onset (≤1 year of age) than in late-onset (>1 year of age) DADA2 patients had high level inflammatory responses, such as elevated ESR, SF, serum amyloid A and CRP. Disease severity was not significantly different from missense and frameshift mutation. Early administration of TNF inhibitor might result in better remission and reduce recurrence. In the literature, four articles describing 51 paediatric DADA2 patients were identified. We also found that fever, stroke, peripheral nervous system involvement, hypogammaglobulinaemia and hypertension were more frequent in early onset DADA2 patients.

Conclusion: Early-onset DADA2 may be more severe. Early administration of TNF inhibitor can effectively reduce recurrence and quickly alleviate the disease.