Reticular dysgenesis (RD) is a rare congenital immunodeficiency classified within the severe combined immunodeficiencies (SCIDs). It is inherited in an autosomal recessive manner, and is characterized by absence of granulocytes and almost complete deficiency of lymphocytes in peripheral blood, hypoplasia of the thymus and secondary lymphoid organs, and lack of innate and adaptive humoral and cellular immune functions, leading to fatal septicemia within days after birth. The bone marrow showed a maturation arrest in the myeloid and lymphoid lineage. The underlying genetic defect for most cases of RD have been identified in the gene encoding adenylate kinase 2 (AK2).