Primary ciliary dyskinesia: the impact of taste receptors (TAS2R38) gene polymorphisms on disease outcome and severity

Background Primary ciliary dyskinesia (PCD) is a rare genetic disease leading to recurrent respiratory infections of upper and lower airways. Chronic rhinosinusitis and bronchiectasis are very common in PCD patients. Recently, it has been shown the presence of taste receptors in respiratory tract and the possible involvement of bitter taste receptor TAS2R38 gene, in susceptibility to respiratory infections and rhinosinusitis. Objective Aim of this study is to evaluate the frequency of TAS2R38 polymorphisms in PCD patients and their possible correlations with clinical outcomes of the disease. Methods Genetic and phenotypic data of 35 PCD patients were collected. Clinical evaluation included: neonatal respiratory distress at birth, presence of situs inversus, chronic rhinosinusitis and bronchiectasis. We also measured number of respiratory infections per year and the relevant pathogens, Lund McKay score, FEV1 and modified Bhalla score (mBhalla). As regards to genetics data, three polymorphisms (rs1726866, rs713598, rs10246939) within TAS2R38 gene were analysed and patients classified as PAV/PAV, PAV/AVI and AVI/AVI. Results A significant difference in the distribution of TAS2R38 haplotype between patients with and without neonatal respiratory distress emerged (p-value=0.01). A lower percentage of PAV/PAV individuals showed frequent respiratory exacerbations (RE) (≥ 2/year) (p-value=0.04) compared to those with AVI/AVI and AVI/PAV haplotypes. Moreover, no patients homozygous for PAV/PAV haplotype presented chronic colonization by Pseudomonas aeruginosa thus supporting the possible role of TAS2R38 gene in susceptibility to respiratory infections. Conclusions. Here we report, for the first time, a possible association of TAS2R38 polymorphisms with PCD phenotype.