Genetic Association Study in Nasal Polyposis

■ Abstract Background and Objectives: Nasal polyposis (NP) is a chronic infl ammatory disease of the upper airways with a variable clinical course and unknown pathogenesis that often coexists with other conditions. Considering the possibility of genetic predisposition, we decided to analyze whether polymorphisms in LTC4S, CYSLTR1, PTGDR, and NOS2A were associated with NP. Methods: The study population comprised 486 Caucasian individuals. Polyposis and aspirin intolerance were diagnosed following the recommendations of the European Position Paper on Rhinosinusitis and Nasal Polyps. Genotypes were determined using polymerase chain reaction amplifi cation and direct sequencing. Results: The –444A>C LTC4S polymorphism was signifi cantly associated with NP and atopy (P=.033) and with NP and atopic asthma, (P=.012). In addition, a signifi cant association was found when the (CCTTT) repetition of the NOS2A gene was present more than 14 times in patients with NP and asthma (P=.034), in patients with polyposis and intolerance to nonsteroidal anti-infl ammatory drugs (P=.009), and in patients with the aspirin triad (P=.005). The PTGDR diplotype CCCT/CCCC (–613CC, –549CC, –441CC and –197TC) was more frequent in patients with NP (P=.043), NP with asthma (P=.013), and the aspirin triad (P=.041). Conclusions: NP was associated with specifi c polymorphisms only when it occurred with related phenotypes. Our results suggest that this genetic background plays a more relevant role in the development of the associated clinical features of nasal polyposis than in simple polyposis.