Linkage Disequilibrium Information within Monozygotic Twin Pairs

Abstract

In conventional GWA studies, only one of monozygotic twin(MZ) pairs are considered because of same genetic information that we fomulate new method for gene-mapping study using resemblance information of phenotypes between MZ cotwins. Our new method used MZ concordance information as dependent variable(binomial trait) that Cochran-Amitage trend test(no covariate) or logis- tic regression(with covariate) was applied. Considering serum triglyceride(TG) or Hypertriglycedemia(hyperTG) traits and rs651821, well-known TG related SNP, power of our association test was calculated via creating simulated pheno- types and we apply our approach to 399 real MZ pairs in Healthy Twin Study, Korea and compare p-value with that of result of GWAS using 1,819 individuals including family structures. In result, rs651821 has some trend with hyperTG traits but is not signicant in various hyperTG cutos as 120, 150, 180, 210, 240(range of p-value: 0.003-0.176). But compared with conventional GWAS in whole autosomal chromosome levels(537,158 SNPs), The authors nd positive association in our new approach and GWAS's results using ROC curves and AUC values. Our methods using new information that concordance of MZ or probability of at least 1 MZ cotwin are aected can contribute gene mapping study.