An unusual family case of ADA-SCID in Russian patients

The mutation of adenosine deaminase leads to a metabolic disorder that causes primary immunodeficiency. It accounts for about 10-20% of all cases of autosomal recessive forms of severe combined immunodeficiency (SCID) in newborns. To the best of our knowledge, the observed mutation variants in our case study with severe combined immunodeficiency have never been reported in the Russian population previously. Two brothers from the same parents had clinical features of typical severe combined immunodeficiency, however, the elder brother died at the age of nine. The clinical picture and laboratory analysis of the younger brother raised the diagnosis of adenosine deaminase deficiency and was screened for the relevant gene mutation(s) through whole-exome sequencing. We detected two mutations in exon 2 and 5 of the adenosine deaminase gene (p.Arg156Cys and p.His156Asp), which we believe is the cause of the severe combined immunodeficiency phenotype observed in our patient. This is the first report of ADA-gene mutations in Sverdlovsk region for Russian patients with severe combined immunodeficiency.