Ataxia-Telangiectasia By James Fernandez, MD, PhD, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University Reviewed / Revised Jan 2023 View Patient Education Symptoms and Signs Diagnosis Treatment Key Points Topic Resources Telangiectasia Ataxia-telangiectasia results from a DNA repair defect that frequently results in humoral and cellular immunodeficiency; it causes progressive cerebellar ataxia, oculocutaneous telangiectasias, and recurrent sinopulmonary infections.