Background: Interleukin 17 (IL-17) plays an important role in many autoimmune diseases including neuromyelitis optica (NMO) and multiple sclerosis (MS), which are inflammatory demyelinating diseases of the central nervous system. A large number of non-HLA single nucleotide polymorphisms have been reported to increase the risk of MS. However, their effects on NMO have been less well studied.

Methods: Fifty-two anti-aquaporin 4 antibody-positive NMO patients, 69 anti-aquaporin 4 antibody-negative conventional MS patients, and 131 controls were genotyped for the IL-17A rs2275913 and IL-17F rs763780 single nucleotide polymorphisms by DNA sequencing.

Results: Significantly higher frequencies of the rs763780 T allele (p(uncorr)=0.011) and TT genotype (p(uncorr)=0.007, p(corr)=0.042) were observed in NMO patients versus controls.

Conclusions: The rs763780 T allele and TT genotype may increase susceptibility to NMO in the Southern Han Chinese.