For example, the catalase activity of IgGs in patients with schizophrenia was approximately 15.8 times higher than in healthy donors [39], and in patients with relapsing and relapsing–remitting multiple sclerosis and patients with secondary progressive multiple sclerosis, it was 2.1 and 1.7 times higher, respectively [30]. The gene discussed is CAT; the disease is schizophrenia.