Primary progress has been made in the last 2 years, particularly in finding novel disease-causing genes for a number of autoinflammatory diseases and primary immunodeficiencies. Whole-exome sequencing has dramatically increased the pace at which causative genes are being discovered. CECR1 (Cat eye syndrome chromosome region, candidate 1) gene encodes adenosine deaminase 2 (ADA2) protein. Patients who carry CECR1 mutation(s) suffer from deficiency of ADA2 (DADA2). Here, we describe a patient with pure red cell aplasia discovered to have DADA2. We also review the literature on DADA2. This report will help raise awareness of physicians for this complex disease.