sequencing and Sanger sequencing to diagnose mutation in the CECR1 gene. They conrmed the mutations using ADA2 enzymatic activity in dried plasma. Eleven patients had mutations in the CERC1 gene, and the median age of patients was 22years. They concluded that DADA2 not only presents with vascular pathology but can sometimes also present as low antibodies. Therefore, all patients with dec antibodies should be screened for DADA2 to prevent missed diagnosis [11]. To diagnose DADA2 cost-effectively, we should measure plasma adenosine deaminase levels before genetic studies [12]. Next-generation sequencing, Sanger sequencing, or whole-exome sequencing can conrm most cases. However, some variants can be missed and need molecular diagnosis using multiplex ligation-dependent probe amplication (MLPA) [13]. Treatment is determined by disease phenotype. TNF inhibitors lower the risk of stroke and decrease inammation. However, it does appear to be effective in patients with bone marrow failure [10]. ADA2 enzyme replacement using fresh frozen plasma was investigated as a treatment option. However, it was not cost-effective due to its short half-life and frequent large vol­ume infusions required to maintain effectiveness. Anti-TNF therapy shows dramatic improvement in symptoms [14]. Anti-TNF started early in the course of the disease and can decrease mortality. Delayed diagnosis and delayed anti-TNF therapy are the leading cause of mortality [15]. When to start treatment in asymptomatic patients and when to stop once symptoms resolve is unknown and must be explored [16]. Hematopoietic stem cell transplant is the denitive treatment. Indications for HSCT are bone marrow failure, immunodeciency, and severe unresponsive vasculi­tis [17].