GLCCI1 Polymorphism rs37973 and Response to Treatment of Asthma With Inhaled Corticosteroids

BACKGROUND

The response to asthma treatment is highly variable, and having pharmacogenetic markers that predict response to treatment would bring us one step closer to personalized treatment. Genome-wide association studies have shown that polymorphisms in GLCCI1 could be associated with the response to inhaled corticosteroids (ICSs) in asthma patients.

MATERIAL AND METHODS

We genotyped rs37973 in GLCCI1 in 208 adult asthma patients treated with ICSs. The percentage change in FEV1, % predicted was analyzed after short-term treatment (3 months) and long-term treatment (at least 3 years). Treatment was defined as successful when FEV1 decreased by <30 mL/year.

RESULTS

After 3 months of treatment, FEV1, % predicted was higher in patients with the GG genotype than in patients with the AG+AA genotype, and this genotype-dependent difference was only evident in nonsmokers. Similar results were found in nonsmokers and patients with atopy after at least 3 years of treatment, when all patients were analyzed. Even though no differences were observed for success of treatment (good vs poor response) when the whole group of patients was analyzed, genotype-dependent treatment success was highly influenced by smoking and atopy. The GG genotype was overrepresented in nonsmokers and patients with atopy and a good response.

CONCLUSIONS

rs37973 was associated with response to short- and long-term treatment; however, smoking and atopy had a considerable effect on pharmacogenetic association. Furthermore, in contrast with findings from genome-wide association studies, we found the GG genotype to be associated with better treatment response.

Polymorphisms and haplotypes of the chromosome locus 17q12-17q21.1 contribute to adult asthma susceptibility in Slovenian patients

One of the major asthma susceptibility loci is 17q12-17q21.1, but the relationship between this locus and adult asthma is unclear. Association analysis of 13 single nucleotide polymorphisms (SNPs) and haplotypes from 17q12-17q21.1 was performed in 418 adult patients with asthma and 288 controls from Slovenia. Single SNP analysis revealed only marginal associations with adult asthma for SNPs located in GSDMA, GSDMB, ORMDL3 and ZPBP2 genes, and rs7219080 was the most highly associated. Analyses of asthma phenotypes found no association with atopy or lung function, but rs2305480 and rs8066582 were associated with childhood asthma and rs9916279 was associated with asthma in smokers. Notably, haplotypes consisting of rs9916279, rs8066582, rs1042658, and rs2302777 harbouring PSMD3, CSF3 and MED24 genes were highly associated with asthma. The four most common haplotypes, TCCG, TTTA, CCCA and TTCA, were more frequent in patients with asthma, whereas TTCG, TCCA, TCTA and TTTG were more frequent in controls. Only 3% of asthma patients belonged to haplotypes TTCG, TCCA, TCTA and TTTG compared with nearly one-third (31%) of controls. Associations confirmed that the 17q12-17q21.1 locus harbours a genetic determinant for asthma risk in adults and suggest that in addition to the previously known ORMDL3-GSDM locus, CSF3-PSMD3-MED24 also plays a role in asthma pathogenesis.

Asthma treatment outcome in adults is associated with rs9910408 in TBX21 gene

Inhaled corticosteroids (ICS) are one of the most commonly used asthma therapies and have highly variable treatment success. Polymorphisms in TBX21, a gene important for the biological action of corticosteroids, could be associated with treatment response in asthmatics. We genotyped for rs9910408 in TBX21 in 208 adult asthmatic patients, treated at least 3 years with ICS. Polymorphism rs9910408 was associated with response to ICS treatment. When treatment success was assessed by a decrease in bronchial hyperresponsiveness (BHR), the frequency of AA genotype was significantly higher in good responders (P = 0.049). This genotype related response was even more evident in the subgroups of non-smokers (P = 0.008) and in non-atopic patients (P = 0.009). AA genotype was overrepresented among good responders according to changes in FEV1 in the subgroups of non-smokers (P = 0.013) and in non-atopic patients (P = 0.048). Our results showed that treatment response to ICS, assessed as changes in BHR and FEV1, is associated with TBX21.