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 Homed 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 Homed 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 Homed 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) =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. Psychiatr Genet 15:277-283 (c) 2005 Lippincott Williams & Wilkins.