Rs10918594

rs10918594, a SNP near the NOS1AP gene encoding the nitric oxide synthase I protein, accounts for some of the variation seen in abnormal heart rhythms, in particular, the QT interval. Based on studies totaling ~4,000 individuals of Caucasian ancestry, homozygotes for one allele have shorter QT intervals, while homozygotes for the other allele have a longer QT interval.

A follow-up study determined that one rs10918594(G) allele was associated with a 3.6-ms (CI: 2.7 - 4.4ms, p=6.9x10(-17)) increase in QT interval duration, and two (G) alleles had twice that increase. No increase in risk for sudden death due to a cardiac problem was associated with this SNP, though.

rs10494366 minor homozygotes had a 9.3 msec longer QT interval compared to major homozygotes (p=5.7x10(-5)); rs10918594 minor homozygotes had a 12.5 msec longer QT interval compared to major homozygotes (p=1.5x10(-6)). Restricting analyses to the diabetic EAs strengthened the effect despite the reduction in sample size (11.3 msec difference, p=5.1x10(-5); 13.9 msec difference, p=1.6x10(-6), respectively).