NOS1 and cystic fibrosis: Also, genetic variations in the baseline nos1 (nNOS) lead to an altered NO production (Texereau et al. 2004; Grasemann et al. 2002; Grasemann et al. 2000), and CF patients harbouring nos1 genotypes are much more susceptible to P. aeruginosa colonisation (Grasemann et al. 2002).