Association of the Val66Met polymorphism of the gene and the deletional mutation of gene with the prevalence and severity of depressive disorder in an Eastern Indian population.

BACKGROUND

The Val66Met single nucleotide polymorphism (SNP) of the brain-derived growth factor (BDNF) and deletional mutation of the cytochrome (CYP2D6) have been reported to be linked to the etiology and severity of depressive disorders (DD) in a variable manner among different ethnicities and populations.

AIMS

The present study was aimed to find the relationship of mutational variations of these two neurotrophins with the severity of DD and their serum cortisol levels as a marker of the stress factor.

METHODS

In 104 drug-naïve newly diagnosed cases of DD and 106 control subjects, the severity of depression was assessed using the HAM-D score. Val66Met SNP of the BDNF was analyzed in them using restriction digestion of its polymerase chain reaction (PCR) product. deletional variants were detected by the absence of their PCR products. Serum cortisol levels were measured by the enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

The Chi-square test (Χ = 1.42, = 0.49) did not show any higher prevalence of Val66Met SNP of the gene in the case group. A correlation coefficient () of -0.14 for HAM-D score with a value of 0.29 signified no direct link of the severity of DD with this SNP. However, a Χ of 12.68 with < 0.001 indicated a significantly higher prevalence of the deletional mutants in DD cases, whereas an -value of 0.39 for HAM-D score with < 0.001 suggested a significantly higher severity of DD having with them. Serum cortisol level showed a significant positive correlation with the deletional variants of ( = 0.198, = 0.04) and the HAM-D score ( = 0.22, = 0.025).

CONCLUSION

We conclude that deletion significantly contributes to the severity and stress factor in the DD patients in our study population. Early identification of these mutations may provide important molecular and cellular predisposition for the disease and may lay the ground for possible more effective measures of intervention.