Influence of monoamine oxidase A gene and brain function in the dynamic facial expression recognition in depressed patients

Abstract

Objective To explore the impact of the variable number of tandem repeats of monoamine oxidase A gene (MAOA-uVNTR) on the intensity of brain activation during the recognition of facial expression in patients with depression and healthy controls.Methods 28 cases of depression,as well as 33 healthy controls who were matched in gender, age and years of education were divided into different genotypes with the methods of polymerase chain reaction (PCR) amplification and 1.5% agarose gel electrophoresis separation.61 cases were scanned to compare the intensity of brain activation in the recognition of happy, sad and neutral facial expression.Results In healthy controls,cases with high-activity genotype showed increased activation in left cuneus,left inferior frontal gyrus, right medial frontal gyrus and left inferior parietal lobule in comparision with carriers of low-activity genotype.In the depressed, compared with patients with low-activity genotype, cases with high-activity genotype decreased activation in bilateral putamen, left postcentral gyrus, left fusiform gyrus, right superior temporal gyrus and right thalamus.Conclusion Healthy controls with high-activity genotype shows the trend of priority for the identification of negative emotion,this genotype may be one of the risk factors for normal people suffering from depression.Patients with high-activity genotype is associated with the inhibitory of positive emotional state, this may attribute partly to the emotional symptoms in such kind of patients more serious. Key words: Major depressive disorders; Monoamine oxidase A gene; Polymorphism