Association study of the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia

Background: Brahma (BRM) is a key component of the multisubunit SWI/SNF complex, a complex which uses the energy of ATP hydrolysis to remodel chromatin. BRM contains an N-terminal polyglutamine domain, encoded by a polymorphic trinucleotide (CAA/CAG) repeat, the only known polymorphism in the coding region of the gene (SMARCA2). We have examined the association of this polymorphism with schizophrenia in a family-based and case/ control study. SMARCA2 was chosen as a candidate gene because of its specific role in developmental pathways, its high expression level in the brain and some evidence of its association with schizophrenia spectrum disorder from genome-wide linkage analysis. Results: Family-based analysis with 281 complete and incomplete triads showed that there is no significant preferential transmission of any of the alleles to the affected offspring. Also, in the case/control analysis, similar allele and genotype distributions were observed between affected cases (n = = 289) and unaffected controls (n = 273) in each of three Caucasian populations studied: French Canadian, Tunisian and other Caucasians of European origin. Conclusion: Results from our family-based and case-control association study suggest that there is no association between the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia.