Quantitative trait locus mapping of these 15 latent factors showed the presence of suggestive QTL on Chr 1, 4, 5, 6, 8 9, 10, 11, 13 and significant QTL on Chr 9 (Factor 3), Chr 10 (Factor 2) and Chr 13 (Factors 1 and 13). Results indicate that multiple factors map onto a single chromosome, for example, distal Chr 13, has suggestive QTL for Factors 1 (76–86 Mbp), 5 (78–84 Mbp, 94–98 Mbp), 6 (75–98 Mbp) and 10 (91–98 Mbp) and significant QTL for Factors 2 (78–80, 88–92 and 94–98 Mbp) and 13 (75–84 Mbp). Factor 15 also maps to Chr 13 but maps to the proximal region rather than the distal region. The Chr 13 genomic region that encompasses the above-mentioned QTL spans 23 Mbp (75–98 Mbp) with a total of 124 genes in the interval. Ninety-six of these 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
