Erythrocyte glutathione is a novel biomarker of Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a congenital red cell aplasia with mutations in ribosomal protein (RP) genes. Elevated activity of erythrocyte adenosine deaminase (eADA) has been utilized as a biomarker of DBA. We examined erythrocyte reduced glutathione (GSH) as well as eADA in 22 patients in 18 DBA families, in whom RP gene mutations had been identified. Simultaneous evaluation of both eADA and GSH demonstrated that all examined DBA patients showed elevated values of either eADA or GSH, whereas presence of both eADA and GSH elevation was able to distinguish DBA patients from 34 normal controls and 14 unaffected members of the DBA families. Furthermore, a support vector machines analysis using both eADA and GSH levels yielded a formula to differentiate DBA from both normal controls and non-DBA family members. To confirm the usefulness of the formula, we analyzed additional 7 patients diagnosed by the clinical criteria. Although eADA showed within normal values in 3 patients, all of these patients were diagnosed as 'DBA' by use of the formula. Because extensive analysis of the RP genes failed to detect no causative mutation in approximately 40% of clinically diagnosed DBA patients, GSH may be useful an additional biomarker for diagnosis of DBA.