Effect of gene polymorphisms in ADAM33, TGFß1, VEGFA, and PLAUR on asthma in Thai population.

BACKGROUND: Most of the asthma susceptibility genes have demonstrated moderate effect. Gene-gene interaction may play a role in asthma. OBJECTIVE: To investigate the genetic and gene-gene interaction effects of single nucleotide polymorphisms (SNPs) in the ADAM33, TGFß1, VEGFA, and PLAUR genes on asthma in Thai population. METHODS: Two hundred and fifty control and 250 asthmatic Thai subjects were recruited. Asthma was diagnosed based on symptoms and spirometry assessments using criteria outlined by the American Thoracic Society. Degrees of asthma severity were determined according to guidelines provided by the Global Initiative for Asthma. Asthmatic subjects were subcategorized into the low-severity (n = 106) and high-severity (n = 144) groups. Eleven SNPs in four genes were genotyped, including ADAM33 SNPs (rs528557/S2, rs598418, rs44707/ST+4), TGFß1 SNPs (rs2241715, rs11466345), VEGFA SNPs (rs833069, rs3025010), and PLAUR SNPs (rs344781, rs344787, rs2239374, rs2239372). Association analyses between SNPs and asthma, and tests for gene-gene interaction were performed. RESULTS: The ADAM33 rs528557/S2 SNP was found to be associated with asthma according to the additive and dominant models. Comparison between the low-severity group and controls showed the VEGFA rs833069 SNP to be significantly associated with the low-severity group. No gene-gene interactions were observed in this study. CONCLUSIONS: The ADAM33 rs528557/S2 and the VEGFA rs833069 SNPs were associated with Thai asthmatics, as well as with other populations worldwide. Further studies are warranted to investigate the use these SNPs as biomarkers for establishing early diagnosis or for predicting future risk of asthma.

Dust mite ingestion-associated, exercise-induced anaphylaxis: a case report and literature review.

BACKGROUND: Oral mite anaphylaxis (OMA) is a condition characterized by severe allergic reactions after ingesting food containing dust mite-contaminated flour. Physical exertion is recognized as a common trigger factor inducing anaphylaxis. The association of OMA with exercise-induced anaphylaxis has rarely been reported. CASE PRESENTATION: We report a 29-year-old Thai woman who had dust mite ingestion-associated, exercise-induced anaphylaxis who tolerated the same bag of contaminated flour without exercise. A sample of contaminated cooking flour was examined under a light microscope. Living mites, Dermatophagoides farinae, were detected by a medical entomologist based on the morphology. We performed skin test to both mite-contaminated and newly opened Gogi® cooking flour, common aeroallergens, food allergens, and all other ingredients in the fried coconut rice cake 5 weeks after the anaphylactic episode. Specific IgE tests, using ImmunoCAP were also performed. CONCLUSIONS: Dust mite ingestion-associated, exercise-induced anaphylaxis may be misdiagnosed as wheat-dependent exercise-induced anaphylaxis and should be suspected in patients with anaphylaxis linked to food intake and exercise, but who have no apparent evidence to the index food ingredients on allergy workup.

Association between ADAM33 polymorphisms and asthma in a Thai population.

ADAM33 (A Disintegrin And Metalloprotease 33) is an asthma susceptibility gene found across several human populations. However, no information on ADAM33 exists for Thai population. The objective of this study was to determine the association, if any, between ADAM33 polymorphisms and asthma in Thai subjects. Genotyping revealed 8 single nucleotide polymorphisms (SNPs) within the 3' region of the ADAM33 gene among 200 asthmatics and 100 control subjects. Asthmatic subjects were further sub-categorized into high and low severity groups. Multiple genetic model statistic tests for single-marker and haplotype association were carried out. Differences in allele frequencies at the SNPs rs528557/S2, rs598418 and rs44707/ST+4 in asthmatics were statistically significant compared to controls. The SNP rs528557/S2 could also be linked to the low severity group and the SNPs rs598418 and rs44707/ST+4 with the high severity group. Two-SNP haplotype analysis at the SNPs rs528557/S2 and rs598418 revealed a significant association with asthma. This study in a Thai population confirmed a positive association between ADAM33 polymorphisms and asthma susceptibility.