MAOA-uVNTR polymorphism in male recidivist violent offenders in the Indian population

An association of MAOA-uVNTR polymorphism with aggression and violence has been demonstrated in many studies; however, this association is inconclusive due to the allelic variation in different populations. Allelic variants and the frequency of this polymorphism among recidivist violent offenders could provide more information about this complex behaviour. Hence, the association between violence and the polymorphism of variable numbers of tandem repeats located upstream of the MAOA gene needs to be ruled out.

Identified recidivist violent offenders by various laws of 'Offences against Human Body and Property' of the Indian Penal Code and natives of the southern state of India, Kerala, were the cases. Individuals without a history of any offences, from the same locality, were taken as controls. DNA extracted from the buccal epithelial cells from the subjects was genotyped using PCR methods for identifying MAOA-uVNTR polymorphism.

In the subjects (n = 67), polymorphism in the promoter region of the MAOA gene, which comprises of 30bp repeats, 3.5 and 4.5 repeat alleles were observed statistically significantly (p = 0.015). Both 3.5 and 4.5 repeat alleles were present in the participants belonging to the control group. All the participants belonging to experiment group had 3.5 repeats only.

This candidate gene-environment interaction (cGxE) may be one of the reasons for the development of psychopathology in violent offenders. This is the first study among offenders in this regard in India, and data generated will be a significant contribution to the aetiology of various psychiatric disorders and population-specific genome database.