genes are polymorphic, among the compelling candidates is Mctp1 (multiple C2 domains, transmembrane 1). Interestingly, Mctp1 has previously been reported to be strongly associated with bipolar disorder in individuals of European ancestry (Scott et al. 2009). The large number of polymorphic genes within Chr 13 QTL intervals could be one possible explanation for the fact that multiple factors map onto the same genomic region.
