Variants of NOS1, NOS2, and NOS3 genes in asthmatics

Nitric oxide (NO) gas concentrations are higher in expired air in asthmatic s, NO is synthesized by three isoforms of NO synthase (NOS) encoded by thre e distinct genes, NOS1, NOS2, and NOS3. Genome-wide searches have identifie d linkages to asthma on chromosomes 7, 12, and 17 where these three genes a re localized. No association study, however, has been reported to date. To test whether variants of NOS1, NOS2, and NOS3 relate to asthma, a genetic a ssociation study was conducted in a British population (n 300). Intragenic microsatellite variants of NOS1 were significantly associated with asthma [ odds ratio (OR) = 2.08, 95% CI: 1.20-3.57 (95% CI), P = 0.008 (Pc = 0.048)] , but not with IgE levels, Neither NOS2 nor NOS3 variants showed any associ ation with asthma nor IgE levels. These findings suggest that NOS1 variants may be a significant contributor to asthma in a British population. (C) 20 00 Academic Press.