Variation in Uteroglobin-Related Protein 1 (UGRP1) gene is associated with allergic rhinitis in Singapore Chinese.

BACKGROUND: Uteroglobin-Related Protein 1 (UGRP1) is a secretoglobulin protein which has been suggested to play a role in lung inflammation and allergic diseases. UGRP1 has also been shown to be an important pneumoprotein, with diagnostic potential as a biomarker of lung damage. Previous genetic studies evaluating the association between variations on UGRP1 and allergic phenotypes have yielded mixed results. The aim of this present study was to identify genetic polymorphisms in UGRP1 and investigate if they were associated with asthma and allergic rhinitis in the Singapore Chinese population. METHODS: Resequencing of the UGRP1 gene was conducted on 40 randomly selected individuals from Singapore of ethnic Chinese origin. The polymorphisms identified were then tagged and genotyped in a population of 1893 Singapore Chinese individuals. Genetic associations were evaluated in this population comparing 795 individuals with allergic rhinitis, 718 with asthma (of which 337 had both asthma and allergic rhinitis) and 717 healthy controls with no history of allergy or allergic diseases. RESULTS: By resequencing the UGRP1 gene within our population, we identified 11 novel and 16 known single nucleotide polymorphisms (SNPs). TagSNPs were then genotyped, revealing a significant association between rs7726552 and allergic rhinitis (Odds Ratio: 0.81, 95% Confidence Interval: 0.66-0.98, P = 0.039). This association remained statistically significant when it was analyzed genotypically or when stratified according to haplotypes. When variations on UGRP1 were evaluated against asthma, no association was observed. CONCLUSION: This study documents the association between polymorphisms in UGRP1 and allergic rhinitis, suggesting a potential role in its pathogenesis.

Genetic variation in BDNF is associated with allergic asthma and allergic rhinitis in an ethnic Chinese population in Singapore.

Allergic diseases affect more than 25% of the world population and result from a complex interplay between genetic and environmental factors. Recent evidence has shown that BDNF (Brain Derived Neurotrophic Factor) could serve as an important marker of allergic disease. Increased levels of BDNF in blood, bronchoalveolar lavage fluid and nasal lavage fluid positively correlate with disease activity and severity in patients with allergic rhinitis (AR), asthma and atopic eczema. However, reports on the association between genetic variation in BDNF and allergic disease have been controversial. This study therefore aims to clarify the relationship between single nucleotide polymorphisms (SNPs) in BDNF and a genetic predisposition to AR and asthma in an ethnic Chinese population of Singapore. Volunteers with a self-reported history of asthma (718 subjects) or a history of AR as determined by a researcher-administered questionnaire (795 subjects) were used in this study, alongside controls with no personal or family history of allergy (717 subjects). The association results identified a significant association for the tagSNP rs10767664 with a significant PDominant=0.0007 and OR=1.3 for AR and PDominant=0.0005 and OR=1.3 for asthma (using a dominant model of association). The haplotype based analysis also identified a significant association further confirming the single SNP association. The SNP rs10767664 is strongly linked (r2=0.95) to the functional polymorphism rs6265 (Val66Met), which has previously been reported to be associated to allergic phenotypes and also shown to affect BDNF expression. BDNF is a therefore a key molecular player in allergy. Further studies on polymorphisms within BDNF may shed light on its role in the pathogenesis of allergic diseases and potentially serve as biomarkers for allergic disease.

Genome-wide association study for atopy and allergic rhinitis in a Singapore Chinese population.

Allergic rhinitis (AR) is an atopic disease which affects about 600 million people worldwide and results from a complex interplay between genetic and environmental factors. However genetic association studies on known candidate genes yielded variable results. The aim of this study is to identify the genetic variants that influence predisposition towards allergic rhinitis in an ethnic Chinese population in Singapore using a genome-wide association study (GWAS) approach. A total of 4461 ethnic Chinese volunteers were recruited in Singapore and classified according to their allergic disease status. The GWAS included a discovery stage comparing 515 atopic cases (including 456 AR cases) and 486 non-allergic non-rhinitis (NANR) controls. The top SNPs were then validated in a replication cohort consisting of a separate 2323 atopic cases (including 676 AR cases) and 511 NANR controls. Two SNPs showed consistent association in both discovery and replication phases; MRPL4 SNP rs8111930 on 19q13.2 (OR = 0.69, P(combined) = 4.46×10(-05)) and BCAP SNP rs505010 on chromosome 10q24.1 (OR = 0.64, P(combined) = 1.10×10(-04)). In addition, we also replicated multiple associations within known candidates regions such as HLA-DQ and NPSR1 locus in the discovery phase. Our study suggests that MRPL4 and BCAP, key components of the HIF-1α and PI3K/Akt signaling pathways respectively, are two novel candidate genes for atopy and allergic rhinitis. Further study on these molecules and their signaling pathways would help in understanding of the pathogenesis of allergic rhinitis and identification of targets for new therapeutic intervention.