Open Access Study protocol

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

Carlos Alfonso Tovilla-Zárate1*, Thelma Beatriz González-Castro2, Isela Juárez-Rojop2, Sherezada Pool García3, Martha Patricia Velázquez-Sánchez3, Mario Villar-Soto4, Alma Genis5, Humberto Nicolini5, María Lilia López-Narváez67 and María Antonia Jiménez-Santos1

Author Affiliations

1 División Académica Multidisciplinaria de Comalcalco, Ranchería Sur, Cuarta Sección, CP 86650 Comalcalco, Tabasco, México

2 Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias de la Salud, Villahermosa, Tabasco, México

3 Hospital General de Comalcalco, Tabasco, Secretaría de Salud, Comalcalco, Tabasco, México

4 Hospital de Alta Especialidad “Gustavo A. Rovirosa P”, Villahermosa, Tabasco, México

5 Instituto Nacional de Medicina Genómica (INMEGEN), Servicios de Atención Psiquiátrica (SAP), Secretaría de Salud, México, DF, México

6 CIGEN, Centro de Investigación Genómica, Comalcalco, Tabasco, México

7 Hospital General de Yajalón, Yajalón, Chiapas, México

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BMC Psychiatry 2014, 14:29  doi:10.1186/1471-244X-14-29

Published: 5 February 2014



Suicidal 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.


We 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%.


Suicidal 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.

Suicide; Serotonin receptor; Association; Mexican population