Comparison of Val66met Polymorphism of BDNF gene in patients of bipolar disorder and healthy controls.

Abstract

IntroductionThe study aims to explore the utility of BDNF Val66Met polymorphism as a potential biomarker in Indian bipolar disorder patients and its correlation with clinical characteristics.ObjectivesGenotyping Val66Met in BDNF geneExploring its association with bipolar disorder (BD).Methods150 consenting BD patients and matched controls were recruited using a case-control study design. BD severity was assessed using Young’s mania rating scale and the Clinical Global Impression - Severity (CGI-S) scale. BDNF Val66Met polymorphism was identified through real-time PCR after DNA extraction. Data was tested for normal distribution. Genotype frequencies between two groups were compared and the Hardy-Weinberg equilibrium assumptions were tested using Chi-Square tests. Clinical-genotypic associations were explored using the Kruskal-Wallis test and confirmed using hierarchical regression.ResultsOur sample had more males (60%) than females (40%) with mean age of 35.05 years. Most patients had established bipolar disorder and were severely ill (CGI: 38.75, YMRS). Val66Met SNP genotype frequency differed significantly between cases and controls. Val66Val genotype and Val allele were higher in cases. Results consistent with Hardy-Weinberg equilibrium.Table 1.Genotype frequencies of BDNF (rs6265) in cases and controlsGENOTYPECCCTTTCASES94(62.6%)47(31.3%)9(6%)CONTROL71(47.3%)69(46%)10(6.6%)CHI-SQUARE- 7.431DF(Degree of freedom) - 2p-value- 0.024Table 2.Dominant genotype frequencies in cases and controlsDOMINANT GENOTYPECCCT+TTCASES94(62.6%)56(37.3%)CONTROLS71(47.3%)79(52.6)CHI-SQUARE-7.125DF(Degree of freedom)-1p-value-0.007Table 3.Allelic frequencies of BDNF (rs6265) in BD cases and healthy controlsALLELIC VARIATIONCTCASES235(78.3%)65(21.6%)CONTROLS211(70.3%)89(29.6%)CHI-SQUARE-5.032DF(Degree of freedom)-1p-value- 0.024ConclusionsOur study found that Val66Val genotype and Val allele were higher in cases and could be a potential biomarker for bipolar disorder (BD), which is consistent with previous research conducted on the European population. However, further investigations are required to gain a more comprehensive understanding of its impact on BD, including its association with serum BDNF levels, treatment outcomes, and a more diverse study population.Disclosure of InterestNone Declared