Identification of Monoaminoxidase/a Gene Promoter Polymorphism (Maoa-Uvntr) and Their Relationship With Aggressive Behavior in Ukrainian Children

Abstract

Aggressive disorders have moderate heritability; therefore, identification of genetic influences is important. The X-linked MAOA gene encoding the MAOA enzyme has a functional polymorphism of 30 bp repeats. in the promoter region (MAOA-uVNTR), which affects aggression. Stressful life events and family misfortune are also known correlates of behavior disorder in children. Objective: to investigate the interactive effect of monoamine oxidase-A gene promoter polymorphism (MAOA-uVNTR) and environmental factors on the development of aggressive behavior. Materials and methods. Genotyping of the MAOA-uVNTR polymorphism was performed in 144 boys and girls aged from 10 to 16 years, genotypes were grouped by a high and low transcriptional activity. For the general assessment of the psycho-emotional sphere of children, the projective method «non-existent animal» was used, the indicators and forms of aggression were determined according to the method of A. Bass and A. Darky. Results and discussion. It was found the predominant allelic variants of the MAOA gene with 3 (S) and 4 (L) tandem repeats. The presence of close relationships between the dependent variable «aggressive behavior» and the predictor variables: «family disadvantage index» and «MAOA-uVNTR genotype» was established. It has been proven that the presence of the highly active allele (L) in the genotype reduces the chances of developing general aggression, delinquent behavior, physical aggression, open aggression, negativism, and externalization. Conclusions. The MAOA genotype of the high-activity allele (L) moderated the impact of stressful life events, and the low-activity allele S was associated with increased aggression in girls and boys who experienced severe stress. Key words: aggressive behavior; MAOA-uVNTR genotype; stressful life events, family misfortune; interactive effect.