They studied the effect of three nonsynonymous variants in this gene on PTC taste sensitivity. They observed the 296V variant is in very strong linkage disequilibrium with 262A (the single exception was an African American subject). The “taster” haplotype for positions 49, 262, and 296 is “PAV”, the “nontaster” haplotype is “AVI” — thus, this variant is associated with the taster group. 81% of homozygotes for AVI were nontasters, as were 52% of AAV/AVI heterozygotes. Individuals carrying at least one copy of “PAV” were overwhelmingly likely to be “taster” (98%), but in the absence of 49P the 262/296 AV seems to be associated with “taster” as well.
The combined P-value of the NIH and Utah samples comparing AAV/AVI to AVI/AVI, using Fisher’s exact test, has p = 0.020.