Mapping Genes for Mammographic Density

We recruited 1,521 women from the Old Order Amish (OOA) population of Lancaster County, Pennsylvania, with the primary goal of identifying genetic factors that influence mammographic density. All women were between the ages of 40 and 88 years, with a mean of 54 years. Additional study design details, including eligibility criteria, are described elsewhere (Douglas et al., 2008). The present-day OOA of Lancaster County are the descendants of approximately 550 individuals from central Western Europe who immigrated to the U.S. in the early eighteenth century. All living individuals derive from a single, 14-generation pedigree (Lee et al., 2010). Although the OOA are a genetically closed founder population, allele frequencies and LD profiles are remarkably similar between the OOA and U.S. participants in the International HapMap project (HapMap CEU) for common SNPs (MAF>/=5%) (Van Hout et al., 2010). We recently completed genome-wide linkage and association analyses of mammographic density, including dense and non-dense areas of the breast and the ratio of dense to total area of the breast. Summary-level data from our GWAS are available here and through the Marker of DEnsity (MODE) Consortium.]]>
We conducted genome-wide association analyses of mammographic density, including dense and non-dense areas of the breast and the ratio of dense to total area of the breast. The Center for Inherited Disease Research (CIDR) genotyped 2,443,179 SNPs using the Illumina HumanOmni2.5-4v1_B Array. Summary-level data are based on 1,472 OOA women, including 723 pre- and 749 post-menopausal women, and the 1,452,421 SNPs that passed our quality-control filters and had a minor allele frequency of at least 1%.We conducted genome-wide association analyses of mammographic density, including dense and non-dense areas of the breast and the ratio of dense to total area of the breast. The Center for Inherited Disease Research (CIDR) genotyped 2,443,179 SNPs using the Illumina HumanOmni2.5-4v1_B Array. Summary-level data are based on 1,472 OOA women, including 723 pre- and 749 post-menopausal women, and the 1,452,421 SNPs that passed our quality-control filters and had a minor allele frequency of at least 1%.We conducted genome-wide association analyses of mammographic density, including dense and non-dense areas of the breast and the ratio of dense to total area of the breast. The Center for Inherited Disease Research (CIDR) genotyped 2,443,179 SNPs using the Illumina HumanOmni2.5-4v1_B Array. Summary-level data are based on 1,472 OOA women, including 723 pre- and 749 post-menopausal women, and the 1,452,421 SNPs that passed our quality-control filters and had a minor allele frequency of at least 1%.All Old Order Amish women were eligible to participate if they were at least 40 years of age at the time of interview. Women were excluded if they were (1) pregnant or lactating in the previous 6 months, (2) had ever been diagnosed with breast or ovarian cancer, (3) had one or both ovaries removed, or (4) used exogenous sex steroid hormones in the previous 6 months.]]>