Joint effects of common genetic variants from multiple genes and pathways on the risk of premature coronary artery disease.
OBJECTIVE
The aim of this study is to discover common variants in 6 lipid metabolic genes and construct and validate a genetic risk score (GRS) based on the joint effects of genetic variants in multiple genes from lipid and other pathobiologic pathways.


BACKGROUND
Explaining the genetic basis of coronary artery disease (CAD) is incomplete. Discovery and aggregation of genetic variants from multiple pathways may advance this objective.


METHODS
Premature CAD cases (n = 1,947) and CAD-free controls (n = 1,036) were selected from our angiographic registry. In a discovery phase, single nucleotide polymorphisms (SNPs) at 56 loci from internal discovery and external reports were tested for associations with biomarkers and CAD: 28 promising SNPs were then tested jointly for CAD associations, and a GRS consisting of SNPs contributing independently was constructed and validated in a replication set of familial cases and population-based controls (n = 1,320).


RESULTS
Five variants contributed jointly to CAD prediction in a multigenic GRS model: odds ratio 1.24 (95% CI 1.16-1.33) per risk allele, P = 8.2 x 10(-11), adjusted OR 2.03 (1.53-2.70), fourth versus first quartile. 5-SNP genetic risk score had minor impact on area under the receiver operating characteristic curve (P > .05) but resulted in substantial net reclassification improvement: 0.16 overall, 0.28 in intermediate-risk patients (both P < .0001). GRS(5) predicted familial CAD with similar magnitude in the validation set.


CONCLUSIONS
The Intermountain Healthcare's Coronary Genetics study demonstrates the ability of a multigenic, multipathway GRS to improve discrimination of angiographic CAD. Genetic risk scores promise to increase understanding of the genetic basis of CAD and improve identification of individuals at increased CAD risk.
Anderson
Jeffrey L
JL
Cardiovascular Department, Intermountain Medical Center, Murray, UT 84107, USA. jeffrey.anderson@imail.org
Horne
Benjamin D
BD
Camp
Nicola J
NJ
Muhlestein
Joseph B
JB
Hopkins
Paul N
PN
Cannon-Albright
Lisa A
LA
Mower
Chrissa P
CP
Park
James J
JJ
Clarke
Jessica L
JL
Nicholas
Zachary P
ZP
McKinney
Jason T
JT
Carlquist
John F
JF
D000328:Adult; D017668:Age of Onset; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012372:ROC Curve; D018570:Risk Assessment