The differences in the level of serum GFAP between patients in the groups we have studied were less dramatic than those reported in a recent study examining levels of GFAP in the cerebrospinal fluid of patients with NMO and MS, where the overall levels of cerebrospinal fluid GFAP measured during a relapse were reported to be 2 476.6±8,815.0 ng/mL in NMO and 0.8±0.4 ng/mL in MS [12]. The gene discussed is GFAP; the disease is neuromyelitis optica.