A clinical case of Louis-Bar syndrome with a clinical picture of cerebellar ataxia and EBV-associated lymphoproliferative syndrome

This description of the clinical case presents the medical history of the child aged 2 years and 6 months with a picture of Louis-Bar syndrome. Manifestations of progressive cerebellar ataxia, bruxism, oculomotor apraxia, and benign lymphoproliferative syndrome caused by Epstein-Barr virus have been reported. No signs of telangiectasia were noted, which may be explained by the age of the child. The immunological study identified signs of combined immunodeficiency with lymphopenia, a decrease in the number of T-helpers and cytotoxic T-lymphocytes in the blood, as well as low serum IgA concentration. The content of alpha-fetoprotein in the serum exceeded the normal upper limit by 15 times. Genetic test revealed three mutations in the ATM gene, in particular two known pathogenic nucleotide substitutions in the heterozygous state — c.8147T>C (p.Val2716Ala) and c.8584+2T>C (Splice donor), and one previously unknown mutation — c.3178A>G (p.fle1060Val) of uncertain diagnostic value in the heterozygous state. Valganciclovir was prescribed to inhibit reproductive activity of Epstein-Barr virus, leukocyte dialysate and propes — to compensate the immunodeficiency, and combination therapy with cerebrocurin and citicoline — for neurological deficits with a partial positive effect. This clinical example demonstrates the potential of a neuroimmunological approach to patient management, as the examined child suffered from both immunodeficiency and neurological dysfunction due to the pleiotropic effects of the mutated gene that caused the disease.