Ataxia-telangiectasia (Louis-Bar syndrome): a clinical case

Ataxia-telangiectasia (Louis-Bar syndrome) is a genetic disorder inherited in an autosomal recessive manner, char­acterized by impaired deoxyribonucleic acid (DNA) repair. Clinically, it manifests as ataxia due to cerebellar degener­ation, telangiectasia, severe immunodeficiency, a predispo­sition to cancer, and increased sensitivity to radiation expo­sure. Signs and symptoms of this primary immunodeficiency disorder are relatively specific; however, the diversity in dis­ease course, multiple neurological symptoms, and variable clinical features often lead to delayed diagnosis and an un­favorable prognosis. Here we present a clinical case of Lou­is-Bar syndrome in 8-year-old patient, in which an extended diagnostic search ultimately led to the correct diagnosis. The first neurological symptoms appeared at the age of 3 months with the formation of clubfoot, strabismus, unsteady gait, and speech disorders by the age of 2. The child has been reg­ularly treated in the neurological department. Immune dys­function was manifested by autoimmune (pauciarticular ju­venile rheumatoid arthritis) and allergic (allergic conjuncti­vitis and insect sting allergy) syndromes, as well as frequent infectious diseases and verified hypogammaglobulinemia. At the age of 8, the patient was sent for examination to the Department of Immunology of the Dmitry Rogachev Na­tional Research Medical Center, where full-exome sequenc­ing was performed and a heterozygous mutation in the ATM c.5932G>T, p.(Glul978Ter) gene was found, thus confirming ataxia-telangiectasia (Louis-Bar syndrome).