Biomarkers in first-degree relatives of patients with bipolar disorder: what can they tell us?

Abstract

association between the BDNF Val66Met polymorphism and memory, we have no such evidence regarding peripheral levels of BDNF. In fact, the BDNF Val66Met SNP does not affect plasma BDNF levels, as pointed out in recent research.6,7 Therefore, unlike Drs. Lipov and Candido, we do not consider the lack of peripheral BNDF measurement a limitation of our study. Nevertheless, we agree that, to better understand the dynamics of the BDNF changes demonstrated in our study, novel approaches to measurement of levels of the corresponding proteins are necessary.Although candidate gene studies have linked the BDNF Val66Met polymorphism with posttraumatic stress disorder (PTSD), a recent meta-analysis did not find a significant overall effect of this SNP on susceptibility to PTSD.8 On the other hand, subgroup analyses suggested that the stress status of the control group could affect the relationship between the BDNF Val66Met polymorphism and PTSD risk. Considering the heterogeneity of findings associating this polymorphism with cognitive performance in elderly adults, our study was designed to investigate the effects of this genetic variant on declarative memory performance specifically in this population. Considering that the percentage of older adults with PTSD is around 3%, 9 the overall impact of this diagnosis in our sample is probably negligible. DisclosureThe authors report no conflicts of interest.