Page 119 - Genomic Medicine in Emerging Economies

108 CHAPTER 6: Neuropsy chiatric Genomics in Latin Americ a

Advances in Molecular Genetics of Psychiatric Disorders
in Latin America
Taking into account the large heritability found for several PDs (Burmeister
et al., 2008) and the huge impacts on public health for some of them, multiple
groups have analyzed genetic risk factors for PDs in Latin American countries
(Table 6.3). As for other complex disorders, the risk for PDs is hypothesized
as being the result from large numbers of variants with small effects. Many
of the candidate genes and variants were chosen from pathways proposed
from biochemical and pharmacological hypotheses or from regions identified
in genome-wide linkage or association studies. Several research groups have
explored the possible association of candidate genes (such as SLC6A3, TPH2,
and BDNF, among others) with PDs, such as alcohol dependence, antisocial
personality disorder, BP, generalized anxiety disorder, obsessive-compulsive dis-
order, autism, eating disorders, MDD, SZ, and suicidal behavior (Alvim-Soares
et al., 2013; Bau et al., 2001; Bertola et al., 2007; Cajal et al., 2012; Campos
et al., 2010, 2011; Cappi et al., 2012; Contini et al., 2012, 2006; Cordeiro et al.,
2012, 2010, 2009a, 2005, 2004; Cuartas Arias et al., 2011; da Silva et al., 2016;
Figueira et al., 2010; Fridman et al., 2003; González-castro et al., 2015, 2013a,b;
Gonzalez et al., 2013; Gregório et al., 2005; Hernandez et al., 2016; Hounie
et al., 2008; Junqueira et al., 2004; Kohlrausch et al., 2016; Longo et al., 2009;
Magno et al., 2010; Marquez et al., 2013; Meira-Lima et al., 2005, 2004; Miguita
et al., 2006, 2007; Moreira et al., 2015; Mota et al., 2013; Neves et al., 2011;
Peralta-Leal et al., 2012; Pereira et al., 2014; Pereira Pde et al., 2011; Prestes
et al., 2007; Rocha et al., 2011; Rocha et al., 2010; Segal et al., 2009; Sesarini
et al., 2015, 2014; Tovilla-Zarate et al., 2013; Urraca et al., 2011; Vasconcelos
et al., 2015). Several meta-analyses for candidate genes have been carried out in
Latin American countries for SZ (González-castro et al., 2016), BP (González-
castro et al., 2015), suicidal behavior (Arboleda et al., 2001; González-castro
et al., 2013a,b), and alcohol dependence (Forero et al., 2015).
Studies in Latin America represent a small fraction of the international liter-
ature in psychiatric genetics research (Gatt et al., 2015), and some of these
genetic works had as an objective the replication of previous findings from
candidates identified in other populations; however, it has been common that
these studies do not confirm previous findings (Gatt et al., 2015). One of the
possible reasons for such inconsistencies may result from the heterogeneity
of the populations or from the differences in the genes involved in the patho-
physiology of these disorders (Burmeister et al., 2008).
Latin American populations provide an interesting setting to study gene-envi-
ronment interactions. These countries are composed of an admixed population
that lives mostly in large cities with frequent social and economic challenges
(such as large numbers of inhabitants with low incomes and the presence of