Two cases of severe combined immunodeficiency caused by adenosine deaminase deficiency with a new mutation and a novel missense mutation in DCLRE1C

Abstract

Severe combined immunodeficiency (SCID)is a potentially fatal primary immunodeficiency in which there is combined absence of T-lymphocyte and Blymphocyte function. There are at least 13 different genetic defects that can cause SCID. SCIDIs the most serious primary or congenital human immunodeficiency disorder. Adenosine deaminase (ADA) deficiency is among the most common causes of severe combined immunodeficiency and is autosomal recessively inherited through mutations in the ADA gene, characterized by dysfunction of the T, B, and natural killer (NK) cells (T-B-NK-SCID) Mutations in the gene for Artemis (DCLRE1C) cause a rare form of autosomal recessive radiosensitive SCID, which results in a T-B-NK+ phenotype. General presentation occurs in infancy with lymphopenia, failure to thrive, diarrhea, candidiasis, and Pneumocystis jiroveci pneumonia. In Artemis deficiencyPatients with an Omenn syndrome phenotype have also been described. Even with supportive therapies, patients with SCID will not survive without aHematopoietic stem cell transplantation (HSCT). Patients transplanted before 3 months of age have a greater survival while patients who are transplanted later and have suffered end organ damage from infections have a much lower success rate. Overall, patients with T-BSCID have less successful HSCT outcomes than patients with T-B+ SCID