Mutant ADA2 in Vasculopathies

To the Editor: Zhou et al.(1) and Navon Elkan et al.(2) (both in the March 6 issue) speculate that hematopoietic stem-cell transplantation (HSCT) or enzyme-replacement therapy may be beneficial in patients with adenosine deaminase 2 (ADA2) deficiency. We report the clinical course of two brothers with recently diagnosed ADA2 deficiency resulting from a homozygous mutation in CECR1 (p.R169Q). One sibling underwent HSCT in 2003. (CECR1 encodes the protein ADA2.) One brother presented in 1999, at 6 months of age, with livedo reticularis, hepatosplenomegaly, hypercoagulability, granulocytopenia, and complete red-cell aplasia. He underwent HSCT in 2003 for a presumed diagnosis of . . .status: publishe