misclassification of ataxia telangiectasia with hyper igm immune profile

Ataxia-telangiectasia is a rare primary immunodeficiency and multisystem dna repair disorder, resulting from mutation in ataxia telangiectasia mutated (atm) gene. the atm protein plays a significant role in detecting dna double-strand breaks (dsb), oxidative stress and other genetic stresses.the atm can directly mention dna ends in repair complexes and directly involve in the repairment of dsbs that are induced during t cell and b cell rearrangement. therefore, increase in the level of serum igm and mainly sinopulmonary recurrent infection, which is indistinguishable from hyper igm syndrome, can be a symptom of some at patients. at patients with class-switched defect are more prone to severe infections, autoimmunity, and lymphoproliferative disorders. in this study an at patient with characteristic features of hyper igm phenotype and lymphoproliferation is investigated.