Browsing by Author "Zeigler-Johnson, C."
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Item Genome-wide association study of prostate cancer in men of African ancestry identifies a susceptibility locus at 17q21.(2011-05-22) Haiman, C. A.; Chen, G. K.; Tettey, Y.; Strom, S. S.; Berndt, S. I.; Kittles, R. A.; Isaacs, W.B.; Ingles, S.A.; Stanford, J.L.; Diver, W.R.; Witte, J.S.; Hsing, A.W.; Nemesure, B.; Rebbeck, T.R.; Cooney, K.A.; Xu, J.; Kibel, A.S.; Hu, J.J.; John, E.M.; Gueye, S.M.; Watya, S.; Signorello, L.B.; Hayes, R.B.; Wang, Z.; Yeboah, E.; Tettey, Y.; Cai, Q.; Kolb, S.; Ostrander, E.A.; Zeigler-Johnson, C.; Yamamura, Y.; Neslund-Dudas, C.; Haslag-Minoff, J.; Wu, W.; Thomas, V.; Allen, G.O.; Murphy, A.; Chang, B.L.; Zheng, S.L.; Leske, M.C.; Wu, S.Y.; Ray, A.M.; Hennis, A.J.; Thun, M.J.; Carpten, J.; Casey, G.; Carter, E.N.; Duarte, E.R.; Xia, L.Y.; Sheng, X.; Wan, P.; Pooler, L.C.; Cheng, I.; Monroe, K.R.; Schumacher, F.; Le Marchand, L.; Kolonel, L.N.; Van Den Berg, D.; Chanock, S.J.; Stram, D.O.; Henderson, B.E.;In search of common risk alleles for prostate cancer that could contribute to high rates of the disease in men of African ancestry, we conducted a genome-wide association study, with 1,047,986 SNP markers examined in 3,425 African-Americans with prostate cancer (cases) and 3,290 African-American male controls. We followed up the most significant 17 new associations from stage 1 in 1,844 cases and 3,269 controls of African ancestry. We identified a new risk variant on chromosome 17q21 (rs7210100, odds ratio per allele = 1.51, P = 3.4 × 10(-13)). The frequency of the risk allele is ∼5% in men of African descent, whereas it is rare in other populations (<1%). Further studies are needed to investigate the biological contribution of this allele to prostate cancer risk. These findings emphasize the importance of conducting genome-wide association studies in diverse populations.Item Population Differences in the Frequency of the Agouti Signaling Protein g.8818A > G Polymorphism(Pigment Cell Research, 2004-04) Zeigler-Johnson, C.; Panossian, S.; Gueye, S.M.; Jalloh, M.; Ofori-Adjei, D.; Kanetsky, P.A.The role of agouti signaling protein (ASIP) in human pigmentation pathways is not definitively understood although its murine homologue regulates, in part, pheomelanogenesis. We have reported an association of a polymorphism in the 3′-untranslated region of ASIP (g.8818A > G) with dark hair and eye color among a group of European-Americans (Am J Hum Genet 2002 March;70:770). Among 147 healthy control subjects, the frequency of the G-allele was 0.12. We hypothesized that this polymorphism would occur at different frequencies among different population groups. Using PCR-RFLP, we genotyped 25 East Asian, 86 African-American, and 207 West African individuals for the ASIP g.8818A > G polymorphism. The g.8818G-allele was present in the West African sample at a frequency of 0.80, in the African-American sample at a frequency of 0.62, and in the East Asian sample at 0.28. The difference in allele frequency among population groups was statistically significant (P < 0.0001). Although the effect of the g.8818A > G polymorphism upon ASIP function is unknown, the large difference in allele frequency between our West African and European-American sample populations lends support to the notion that this gene may be important in human pigmentation.