Gene mutations that are known to alter the response to asthma therapy include Arg/Arg atr position 16, mutations of LTC4S, ALOX5, and GR/NR3C1, increased expression of GR , CRHR1 variants, and mutations in CYP1A2 (-22964 [G/A]), and T 314 allele for histamine N-methyltransferase.
The variant HNMT allele frequencies were slightly higher among patients with asthma [16.0%, 95% confidence interval (CI) 12.0-20.0] and among patients with rhinitis (13.2, 95% CI 10.3-16.1) as compared with healthy subjects (11.5 95% CI 8.9-14.1).
The variant HNMT allele frequencies were slightly higher among patients with asthma [16.0%, 95% confidence interval (CI) 12.0-20.0] and among patients with rhinitis (13.2, 95% CI 10.3-16.1) as compared with healthy subjects (11.5 95% CI 8.9-14.1).
Thus, consistent with the case-control findings, the polymorphisms and haplotypes in the HNMT gene are not associated with asthma in the Indian population.
The association between a common, functionally significant genetic polymorphism for HNMT and asthma suggests that individual variation in histamine metabolism might contribute to the pathophysiology and/or response to therapy of this disease.