Page 122 - Genomic Medicine in Emerging Economies

Introduction 111

high rates of unemployment and violence) (Cia et al., 2010). These popula-
tions, which have a considerable amount of people living in environments
with higher risk to develop PDs, provide a useful setting to study how genes
and environmental risk factors act together to lead to vulnerability or resilience
to mental illness.

There are very few studies that have analyzed epigenetic markers or gene-environ-
ment interactions for PDs in Latin America (Lima et al., 2015). Recently, telomere
attrition has been studied in South American samples because of the potential
relationship between telomere shortening and psychological and biological
stress in PDs, such as BP and ADHD (Costa Dde et al., 2015; Lima et al., 2015),
taking advantage of the potentials of studying individuals from populations
with particular genetic and environmental features (Mitchell et al., 2014).
In recent years, several Latin American research groups have joined interna-
tional initiatives to identify regions and genes, including CNVs, associated
with some PDs, such as obsessive-compulsive disorders and Tourette syndrome
(Nag et al., 2013; Scharf et al., 2013; Stewart et al., 2013).

Molecular Genetics and Neuropsychiatric Endophenotypes in
Latin America
Considering the importance of the study of endophenotypes in NPG (Flint and
Munafo, 2007), several groups have researched candidate genes for intermediate
phenotypes of neuropsychiatric relevance (Table 6.4). Some studies have been
carried out on healthy subjects (Cruz-Fuentes et al., 2014; Forero et al., 2016a;
Gonzalez-Giraldo et al., 2015a,b,c; Gonzalez-Giraldo et al., 2016b,c; Gon-
zalez-Giraldo et al., 2014; Ojeda et al., 2014a,b; Ojeda et al., 2013; Perea
et al., 2014; Solís-ortiz et al., 2010; Speck-Hernandez et al., 2015) and oth-
ers on patients diagnosed with, for example, with ADHD, BP, or SZ (Agudelo
et al., 2015; Akutagava-Martins et al., 2016; Fresan et al., 2007; González-castro
et al., 2015; González-castro et al., 2013b; Guimaraes et al., 2009b; Lopez-Nar-
vaez et al., 2015; Morales-Marin et al., 2016; Salatino-Oliveira et al., 2016a,b;
Salatino-Oliveira et al., 2012b; Salatino-Oliveira et al., 2015; Tovilla-Zarate
et al., 2014; Tovo-Rodrigues et al., 2013; Zeni et al., 2016). These studies have
mainly used validated psychological scales and tests, some of them employ-
ing computerized platforms, to determine functioning in multiple behavioral
dimensions and their correlations with variants in candidate genes.

The list of candidate genes studied for neuropsychiatric endophenotypes in
Latin America includes the following: BDNF, COMT, MAOA, DRD4, SLC6A4,
and PER3, among others. Studies in healthy subjects have evaluated endophe-
notypes related with working memory, circadian rhythm, aggressiveness, and
depressive symptoms. On the other hand, works in patients with neuropsychi-
atric diseases in Latin America have analyzed verbal working memory, suicidal