Any defects in phagocytosis results in impaired apoptosis machinery and results in a defective immune response and may cause susceptibility to various diseases including autoimmunity, chronic granulomatous disease, myeloperoxidase (MPO) deficiency, Chediak–Higashi syndrome, lazy leukocyte syndrome, leukocyte adhesion deficiency, Job’s syndrome, and chemotactic disorders [28]. The gene discussed is MPO; the disease is leukocyte adhesion deficiency.