Rs1695

This SNP, in the GSTP1 gene influences asthma risk; the (A) allele encodes the Ile, while the (G) allele encodes the Val. This SNP is also known as GSTP1Val105, or GSTP1 Ile105Val.

Despite evidence of antioxidant effects of vitamin E in vitro and in animal studies, large, randomized clinical trials have not substantiated a benefit of vitamin E in reducing inflammation in humans. In healthy control subjects, the effect of &#945;-tocopherol supplementation on the production of inflammatory cytokines appears to be dependent on an individual's genotype. These genotype-specific differences may help explain some of the discordant results in studies that used vitamin E. Persons having the alleles AA or AG had an increase in interleukin-6 (IL-6) upon supplementing alpha-tocopherol (the most common form of Vitamin E in a North American diet) while those with GG saw a decrease.

This research paper shows that 13- to 21-year-olds exposed to tobacco smoke at home, with this mutation had more severe asthma than those without the mutation. rs1695 is also mentioned in this bbc article

Several papers published findings associating GSTP1 Ile105Val genotypes with bronchial, childhood, or atopic asthma.

Note that some studies, however, have not observed any association between this SNP and asthma in certain populations, or even more paradoxically, have observed that rs1695(G;G) homozygotes appear to be somewhat protected (OR 0.29) from developing asthma compared to individuals with rs1695(A;G) or (A;A) genotypes.

A cohort of 1,610 children in the US were studied to determine that the risk for new-onset asthma was highest in rs1695(A;A) homozygotes who participated in 3 or more sports in high-ozone communities. These children were at 6x higher risk (CI: 2.2-7.4).

A study of 3,000 Chinese women with breast cancer concluded that rs1695(G;G) genotype was significantly associated with greater breast cancer risk, particularly in premenopausal women (odds ratio 1.69, CI: 1.17-2.43). The odds increased further if such women reported eating little cruciferous vegetables (then the odds ratio was 2.08, CI: 1.20-3.59).

A relatively small study of 58 patients with different types of cancer receiving docetaxel concluded that rs1695(A;A) homozygotes (i.e. Ile105/Ile105 homozygotes) had a higher risk of developing docetaxel-induced peripheral neuropathy (DIPN), particularly grade 2 or higher. The odds ratio reported was 6.1 (CI: 1.17-31.9, p=0.03).