Abstract
BACKGROUND: Severe combined immunodeficiency (SCID) is a group of relatively rare primary immunodeficiency disorders (PIDs), characterized by disturbed development of T cells and B cells, caused by several genetic mutations that bring on different clinical presentations. SCID may be inherited as an autosomal recessive or an X-linked genetic trait. CASE PRESENTATION: A 6-year-old male presented with a history of food allergy, productive coughs, and recurrent purulent rhinitis, poor weight gain and hypothyroidism. The total count of CD4+ T lymphocytes, along with their naïve and central memory subpopulations, as well as central memory CD8+ T cells were decreased in flow cytometry. A nucleotide substitution in exon one of interleukin 2 receptor gamma chain (IL-2RG) gene (c.115 G>A, p.D39N, ChrX: 70,331,275) was reported, based on which the diagnosis of X-liked SCID was confirmed. Antiviral and antibiotic prophylaxis, along with monthly IVIG (intravenous immunoglobulin) was started and the patient was subsequently referred for hematopoietic stem cell transplantation. CONCLUSION: PIDs should be considered as the differential diagnosis in any patient with unexplained and bizarre symptoms associated with recurrent infections, allergic and autoimmune manifestations. Clinicians should also bear X-SCID in mind in case of approach to any patient with poor weight gain, unusual allergic or endocrine manifestations, even in the case of a normal or increased level of serum immunoglobulins or T and B cells numbers.