WAS and chronic granulomatous disease: Gene therapy using iPSCs has also been used to treat various primary immunodeficiencies like Chronic Granulomatous disorder (CGD), an autosomal recessive or X-linked disorder which affects the function of neutrophils, and Wiskott–Aldrich syndrome (WAS), X-linked deficiency caused by mutation in WAS gene encoding WAS protein (WASp) which is an actin cytoskeletol regulator in hematopoietic lineage (Klein et al., 2003; Jiang et al., 2012).