Common CYP7A1 promoter polymorphism associated with risk of neuromyelitis optica.

Neuromyelitis optica (NMO) is a severe idiopathic inflammatory disease of the central nervous system primarily affecting the optic nerves and spinal cord. In this study, we generated genome-wide SNP data from NMO patients and normal controls (53 cases and 240 controls), and followed up on the association signals with samples from a larger number of inflammatory demyelinating diseases, including NMO (n=93), multiple sclerosis (MS, n=71), idiopathic recurrent transverse myelitis (IRTM, n=57), and normal controls (n=240). Statistical analyses revealed that a common promoter SNP in CYP7A1 has a protective/gene dose-dependent effect on the risk of NMO (P=0.0004). A stronger association between the variables and subsequently, a higher protective effect (lower OR) on the risk of NMO were observed among patients carrying the "G/G" genotype of rs3808607 than those with the "T/G" genotype (OR=0.38/P=0.01 vs. OR=0.12/P=0.0004, respectively). The associations which were only observed in patients with NMO suggest that there are differences in the genetic etiology of the inflammatory demyelinating diseases (NMO, classical MS, and IRTM).

53 Korean ancestry cases, 240 Korean ancestry controls