Aquaporin-4 Gene Polymorphisms in Neuromyelitis Optica and Recurrent Optic Neuritis

Abstract

Objective: Although Aquaporin-4 (Aqp-4) gene polymorphisms have been extensively studied in neuromyelitis optica spectrum disorder (NMOSD), there is little evidence on the involvement of Aqp-4 in the pathogenesis of relapsing optic neuritis (RON). Materials and Methods: In our study, we recruited patients who were followed by Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Multiple Sclerosis and Myelin Disorders Unit between 1979 and 2015. Blood samples of the patients were genotyped for potential variants in the exons and the nearby regions of Aqp-4 gene. Results: The Aqp-4 gene was sequenced in 15 patients with RON who were seronegative, 33 patients with NMOSD, and 30 healthy controls. None of the patients showed previously described single nucleotide polymorphisms (SNPs). Three new SNPs were identified in non-exonic regions of the gene. One intronic SNP located in close proximity to the fifth exon had a higher prevalence in patients with RON than patients with NMOSD and healthy controls. Conclusion: Aqp-4 SNPs show a considerable heterogeneous geographic distribution and might be involved in RON pathogenesis.

Keywords

• neuromyelitis optica
• recurrent optic neuritis
• polymorphism aquaporin-4