Study on genes of the serotonergic system and suicidal behavior: protocol for a case–control study in Mexican population

Abstract

BackgroundSuicidal behavior is a leading cause of injury and death worldwide. Several studies have provided a possible relationship between genetic factors and suicidal behavior. Also, these studies have shown evidence for altered serotonergic neural transmission in the pathogenesis of suicidal behavior. In addition, genes pertaining to the serotonergic system have been proposed as candidates to establish biological correlates between suicidal behavior and the serotonergic system. The most studied genes are SCL6A4, HTR2A, HTR2C, HTR1A, HTR1B, TPH-1, and TPH-2. To get a comprehensive understanding of the association with suicidal behavior we will conduct genotype assays studies in a Mexican population.Methods/DesignWe will conduct a case–control study. The population sample will comprise adolescent and adult patients admitted for attempted of suicide and diagnosed by a psychiatrist. A peripheral blood sample will be taken from all the subjects (cases and controls). Genomic DNA from the leukocytes blood sample will be extracted. The genotypes of interest are distributed in the following genes: SCL6A4, HTR2A, HTR1A, HTR1B, HTR2C, TPH-2 and TPH-1. All the samples will be analyzed using a polymerase chain reaction (PCR) end-point method. We will evaluate the Hardy-Weinberg Equilibrium. The chi-squared test or Fisher’s exact test will be used to compare genotype and allele frequencies between control and case groups. The Quanto 1.2 software will measure the sample size of the association. For all the association analyses the level of significance will be set at p = 0.05 and the confidence interval at 95%.DiscussionSuicidal behavior has been increase in Mexico, principally in young population. Our study will demonstrate the association between serotoninergic genes and suicide behavior in Mexican population.

Differences Between Patients that Made an Impulsive or Premeditated Suicide Attempt in a Mexican Population

“…Many factors are involved in suicidal behavior. Several studies have suggested that biological, social, individual, and environmental factors are involved in this behavior [7, 8]. The literature repeatedly shows that suicide attempts are often impulsive [9, 10].…”

Association between serotonin 2C receptor gene (HTR2C) polymorphisms and psychopathological symptoms in children and adolescents

“…However, when exposed to emotion-inducing stimuli, such as stress, anger, and sadness, subjects with the G allele had significantly lower cortisol activation (P<0.001), less anger (P=0.08), and a less depressive mood (P=0.006). The SNPs were also found to be associated with norepinephrine turnover, which was most highly correlated with the rs6318 SNP ( 30 – 33 ). The altered expression of the HTR2C gene may therefore be associated with increased operation of the hypothalamic-pituitary-adrenal axis and with greater amygdala reactivity ( 34 , 14 ).…”

Prioritization and comprehensive analysis of genes related to major depressive disorder

“…Most of these genes, such as PCDH9 , MDD1 , MDD2 , CREB1 and DISC1 , have been identified to be associated with MDD (Cacabelos, Torrellas, & Fernandez‐Novoa, ; Xiao et al, ), and some of them (e.g. TPH1, GRIN2B and MAOA) were also related to other mental disorders (van Donkelaar et al, ; Perlis, ; Tovilla‐Zarate et al, ). This indicated that our preferred solution designed was able to be utilized to get the expected data.…”