Novel loci, including those related to Crohn disease, psoriasis, and inflammation, identified in a genome-wide association study of fibrinogen in 17 686 women: the Women's Genome Health Study.
BACKGROUND
Fibrinogen is a multifunctional circulating glycoprotein involved in wound healing, thrombosis, platelet aggregation, and inflammation, and elevated levels predict vascular disease. Despite evidence of crucial biological function and moderate heritability, comprehensive analysis of the influence of genetic variation on fibrinogen is not available.


RESULTS
To address this issue, we undertook a genome-wide association study evaluating the potential relationships between 337 343 single-nucleotide polymorphisms (SNPs) and plasma fibrinogen levels among 17 686 apparently healthy women participating in the Women's Genome Health Study. As C-reactive protein is also an inflammatory marker known to predict cardiovascular diseases, we compared the determinants of fibrinogen levels with those of C-reactive protein. Four novel loci were identified, in addition to the fibrinogen gene cluster, which were associated with fibrinogen levels at genome-wide levels of significance (range of probability values from 8.82 x 10(-09) to 8.04 x 10(-39)). Two of the loci are related to common chronic inflammatory diseases: the first, at locus 5q31.1 (SLC22A5, SLC22A4, IRF1), lies immediately adjacent to a locus linked to Crohn disease (P value for lead SNP, 1.24 x 10(-12)) and the second, at locus 17q25.1 (CD300LF, SLC9A3R1, NAT9), has been associated with psoriasis (P value for lead SNP, 7.72 x 10(-11)). A third locus at 1q21.3 (IL6R) lies within the interleukin 6 receptor gene, a critical component of the inflammatory cascade (P value for lead SNP, 1.80 x 10(-11)). A novel locus at 2q34 (CPSI) participates in the urea cycle (P=8.82 x 10(-09)). The majority of implicated SNPs showed little evidence of dual association with C-reactive protein levels.


CONCLUSIONS
A genome-wide survey of the human genome identifies novel loci related to common chronic inflammatory diseases as genetic determinants of fibrinogen levels, in addition to loci that relate to the inflammatory cascade, the urea cycle, and the fibrinogen gene cluster.
Danik
Jacqueline S
JS
Center for Cardiovascular Disease Prevention, Donald W. Reynolds Center for Cardiovascular Research, and Translational Medicine Division, Brigham and Women's Hospital, 900 Commonwealth Ave. East, Boston, MA 02215, USA.
Paré
Guillaume
G
Chasman
Daniel I
DI
Zee
Robert Y L
RY
Kwiatkowski
David J
DJ
Parker
Alex
A
Miletich
Joseph P
JP
Ridker
Paul M
PM
D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D003424:Crohn Disease / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005340:Fibrinogen / Q000235:genetics* / Q000378:metabolism; D056426:Genetic Loci; D055106:Genome-Wide Association Study; D006801:Humans; D007249:Inflammation / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011565:Psoriasis / Q000235:genetics* / Q000378:metabolism; D016387:Women's Health
D005340:Fibrinogen; D002097:C-Reactive Protein