Helicobacter pylori, iron deficiency, and gastric autoimmunity.

gene mutations by bidirectional genomic sequencing. Six mutant alleles were found in these cases, 5 previously reported (3242A T, 2129C T [2 patients], 1910A G, and 2287C T) together with a previously unreported 3 base pairs in frame deletion. resulting in deletion of valine 372. In 4 of the 6 sporadic cases, only 1 mutation in the CDAN1 gene could be demonstrated, a situation also seen in half of the sporadic cases described previously,3–5 and in 1 case, with multiple dysmorphic features, no mutations were detected. Mutations in regions of the CDAN1 gene that were not sequenced (promoter, introns) or in regulatory sequences may explain these findings. Given the genetic heterogeneity of this condition, however, it is plausible that a mutation in a second gene could interact with a CDAN1 mutation to result in the CDA I phenotype as a result of digenic inheritance. A more comprehensive understanding of CDA I will require a better knowledge of the function of CDAN1 protein, its cellular distribution and intracellular localization, and the existence of any putative binding partners. The genetic heterogeneity demonstrated here indicates that this should be a fruitful field for the study of erythropoiesis. Momin R. Ahmed, Aref Chehal, Laila Zahed, Ali Taher, Joud Haidar, Ali Shamseddine, Anne-Marie O’Hea, Nicola Bienz, Orly Dgany, Nili Avidan, Jacqui S. Beckmann, Hannah Tamary, Douglas Higgs, Paresh Vyas, William G. Wood, and Sunitha N. Wickramasinghe