Association of a polymorphism in the Homer1 gene with cocaine dependence in an African American population.
OBJECTIVE
While twin and adoption studies have demonstrated that up to 70% of the risk for becoming addicted to cocaine is due to genetic factors, identifying specific genes involved in the development or progression of cocaine dependence has been difficult. The purpose of this study is to determine whether single-nucleotide polymorphisms in the Homer1 and Homer2 genes associate with the cocaine-dependent phenotype in an African American population.


METHODS
This study utilized a case-control design in which the genotype and allele frequencies for four single-nucleotide polymorphisms in the Homer1 gene and three single-nucleotide polymorphisms in the Homer2 gene were compared between African American individuals with a diagnosis of cocaine dependence (n=170) and African American individuals with no history of substance abuse (n=90).


RESULTS
The data indicate that one single-nucleotide polymorphism, rs6871510, located in intron 1 of the Homer1 gene significantly (P=0.029) associates with cocaine dependence at the genotype level, and trends toward a significant association at the allele frequency level (chi=2.62, df=1, P=0.106, OR=1.71). None of the single-nucleotide polymorphisms analyzed in the Homer2 gene associates with cocaine dependence.


CONCLUSIONS
The results of this study suggest that a polymorphism in the Homer1 gene, rs6871510, is a potential risk factor for the development of cocaine dependence in an African American population, whereas polymorphisms in the Homer2 gene are not.
Dahl
John P
JP
Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania School of Medicine, Clinical Research Building, Philadelphia, 19104, USA. jdahl@mail.med.upenn.edu
Kampman
Kyle M
KM
Oslin
David W
DW
Weller
Andrew E
AE
Lohoff
Falk W
FW
Ferraro
Thomas N
TN
O'Brien
Charles P
CP
Berrettini
Wade H
WH
D044383:Black People / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D019970:Cocaine-Related Disorders / Q000235:genetics*; D000072233:Homer Scaffolding Proteins; D006801:Humans; D010414:Pennsylvania; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D020033:Protein Isoforms / Q000235:genetics; D001741:Black or African American
D002352:Carrier Proteins; C000606614:HOMER1 protein, human; D000072233:Homer Scaffolding Proteins; D020033:Protein Isoforms