M S Siva Prasad1, Y Shibu Vardhanan2, S P Shaji Prabha3, Jayesh K Joseph4, Embalil Mathachan Aneesh5

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

1M.Sc. Forensic Science Program, University of Calicut, Kerala Police Academy, Kerala, India
2Department of Zoology, University of Calicut, Malappuram, Kerala, India
3Chemical Examiner’s Laboratory, Department of Home, Thiruvananthapuram, Kerala, India
4Kerala Police Academy, Thrissur, Kerala, India
5Communicable Disease Research Laboratory (CDRL), Department of Zoology, St. Joseph’s College, Thrissur, Kerala, India

Abstract
Aim of the study: 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.
Materials and methods: 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.
Results: In the subjects (n = 67), polymorphism in the promoter region of the MAOA gene, which comprises of 30 bp
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.
Conclusions: 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.
Key words: aggression, violence, polymorphism, MAOA, allelic frequency, serotonin.

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