Supplementary Material for: <i>DTNBP1 (Dystrobrevin Binding Protein 1)</i> and Schizophrenia: Association Evidence in the 3′ End of the Gene

<i>Objectives:</i><i>Dysbindin</i> (<i>DTNBP1</i>) has been identified as a susceptibility gene for schizophrenia (SZ) through a positional approach. However, a variety of single nucleotide polymorphisms (SNPs) and haplotypes, in different parts of the gene, have been reported to be associated in different samples, and a precise molecular mechanism of disease remains to be defined. We have performed an association study with two well-characterized family samples not previously investigated at the <i>DTNBP1</i> locus. <i>Methods:</i> We examined 646 subjects in 136 families with SZ, largely of European ancestry (EA), genotyping 26 SNPs in <i>DTNBP1</i>. <i>Results:</i> Three correlated markers (rs875462, rs760666, and rs7758659) at the 3′ region of <i>DTNBP1 </i>showed evidence for association to SZ (p = 0.004), observed in both the EA (p = 0.031) and the African American (AA) subset (p = 0.045) with the same over-transmitted allele. The most significant haplotype in our study was rs7758659-rs3213207 (global p = 0.0015), with rs3213207 being the most frequently reported associated marker in previous studies. A non-conservative missense variant (Pro272Ser) in the 3′ region of <i>DTNBP1</i> that may impair <i>DTNBP1</i> function was more common in SZ probands (8.2%) than in founders (5%) and in dbSNP (2.1%), but did not reach statistical significance. <i>Conclusion: </i>Our results provide evidence for an association of SZ with SNPs at the 3′ end of <i>DTNBP1</i> in the samples studied.