A genome-wide association study of total bilirubin and cholelithiasis risk in sickle cell anemia.

Pubmed ID: 22558097

Pubmed Central ID: PMC3338756

Journal: PloS one

Publication Date: Jan. 1, 2012

Affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, United States of America.

MeSH Terms: Humans, Risk Factors, Cohort Studies, Polymorphism, Single Nucleotide, Anemia, Sickle Cell, Bilirubin, Cholelithiasis, Genome-Wide Association Study, Genotype, Glucuronosyltransferase, Inheritance Patterns, Isoenzymes, Principal Component Analysis, Black or African American

Grants: 1RC2HL101212, T32 HL007501, RC2 HL101212

Authors: Milton JN, Sebastiani P, Solovieff N, Hartley SW, Bhatnagar P, Arking DE, Dworkis DA, Casella JF, Barron-Casella E, Bean CJ, Hooper WC, DeBaun MR, Garrett ME, Soldano K, Telen MJ, Ashley-Koch A, Gladwin MT, Baldwin CT, Steinberg MH, Klings ES

Cite As: Milton JN, Sebastiani P, Solovieff N, Hartley SW, Bhatnagar P, Arking DE, Dworkis DA, Casella JF, Barron-Casella E, Bean CJ, Hooper WC, DeBaun MR, Garrett ME, Soldano K, Telen MJ, Ashley-Koch A, Gladwin MT, Baldwin CT, Steinberg MH, Klings ES. A genome-wide association study of total bilirubin and cholelithiasis risk in sickle cell anemia. PLoS One 2012;7(4):e34741. Epub 2012 Apr 27.

Studies:

Abstract

Serum bilirubin levels have been associated with polymorphisms in the UGT1A1 promoter in normal populations and in patients with hemolytic anemias, including sickle cell anemia. When hemolysis occurs circulating heme increases, leading to elevated bilirubin levels and an increased incidence of cholelithiasis. We performed the first genome-wide association study (GWAS) of bilirubin levels and cholelithiasis risk in a discovery cohort of 1,117 sickle cell anemia patients. We found 15 single nucleotide polymorphisms (SNPs) associated with total bilirubin levels at the genome-wide significance level (p value <5 × 10(-8)). SNPs in UGT1A1, UGT1A3, UGT1A6, UGT1A8 and UGT1A10, different isoforms within the UGT1A locus, were identified (most significant rs887829, p = 9.08 × 10(-25)). All of these associations were validated in 4 independent sets of sickle cell anemia patients. We tested the association of the 15 SNPs with cholelithiasis in the discovery cohort and found a significant association (most significant p value 1.15 × 10(-4)). These results confirm that the UGT1A region is the major regulator of bilirubin metabolism in African Americans with sickle cell anemia, similar to what is observed in other ethnicities.