The rs6265 Polymorphism of the BDNF Gene Is Related to Higher-Lethality Suicide Attempts in the Korean Population

Val/Met BDNF as a genetic risk for a false sense of security in post-discharge suicide risk

BACKGROUND

The time after discharge from psychiatric inpatient care is one of the most dangerous periods in terms of suicide risk. Predicting who is at higher risk could help with resource allocation to assure patients at high risk of suicide attempts are most closely followed. We previously showed that inpatients who improve their suicide ideation levels faster while in inpatient treatment are the ones with highest rates of post-discharge suicide. Here, we studied the possible genetic underpinnings associated with such risk.

METHOD

We recorded the slope of suicide ideation recovery of 710 psychiatric inpatients from which we studied two genetic variants likely associated with suicide risk: The serotonin transporter variant 5-HTTLPR, and the BDNF gene variant Val66Met.

RESULTS

We found that inpatients carrying the BDNF Met variant (hypothesized as conferring higher suicide risk) improved their suicide ideation scores faster than Val/Val carrying inpatients. No significant association was found for 5-HTTLPR.

LIMITATIONS

The present sample was genetically homogenous, and future research should replicate these findings on a more diverse sample.

CONCLUSIONS

In conclusion, we found a paradoxical result: Carrying the BDNF Met variant allows inpatients to improve faster, which was shown to confer higher risk at the post-discharge period. This may explain some inconsistencies in the literature in terms of the role of BDNF in suicide ideation and attempts.

Risk and Protective Factors for Childhood Physical Abuse and Suicidal Ideation: The Effect of Brain-Derived Neurotrophic Factor Polymorphism and Social Support

OBJECTIVE

This study aimed to explore the relationship between childhood physical abuse and suicidal ideation considering the effects of genetic and environmental factors in patients with post-traumatic stress disorder (PTSD) by focusing on brain-derived neurotrophic factor (BDNF) polymorphism and social support, respectively.

METHODS

One-hundred fourteen patients with PTSD and 94 healthy controls (HCs) were genotyped with respect to BDNF Val66Met polymorphism. All participants underwent psychological assessments. The hierarchical regression analysis and the simple slope analysis were conducted.

RESULTS

As for patients with PTSD, the moderation effect of BDNF polymorphism was significant but not for social support. Specifically, the BDNF Val/Val genotype worked as a risk factor and strengthens the relationship between childhood physical abuse and suicidal ideation. As for the HCs, the significant moderation effect was found only in social support, but not for BDNF polymorphism. The relationship between childhood physical abuse and suicidal ideation was weakened for the HCs with high social support.

CONCLUSION

This study demonstrated a significant BDNF genetic vulnerability for suicide in patients with PTSD who experienced childhood physical abuse. Our results suggested that social support provided a mitigating effect on the relationship between childhood physical abuse and suicidal ideation only in the HCs.

BDNF Genetic Variant and Its Genotypic Fluctuation in Major Depressive Disorder

Major depressive disorder (MDD) still has an unknown etiology and mechanisms. Many studies have been conducted seeking to associate and understand the connection of different genetic variants to this disease. Researchers have extensively studied the brain-derived neurotrophic factor (BDNF) Val66Met genetic variant in MDD; yet, their findings remain inconsistent. This systematic review sought to verify the GG (Val/Val) genotype frequency fluctuation in different populations with MDD. For this, we searched in different databases and, after applying the eligibility criteria, selected 17 articles. Most studies demonstrate the higher frequency of the ancestral (wild) GG (Val/Val) genotype, although associations of the polymorphic A (Met) allele, changes in BDNF protein serum levels, or both were also found in MDD, whether related to the disease's development or other factors. Nevertheless, despite these findings, disagreements between several studies are seen. For this reason, further BDNF Val66Met genetic variant studies should not only bridge the gap in the knowledge of this polymorphism's role in MDD's different facets but also analyze the genotypic and phenotypic heterogeneity in different populations to help provide a better quality of life for patients.

Val66Met polymorphism is associated with decreased likelihood for pediatric headache and migraine

Background: Migraine is a complex multifactorial disorder and its pathogenesis still remains unclear. Evidence suggests the involvement of the activated trigeminovascular pathway, in which BDNF seems to play an important role. Therefore, BDNF polymorphisms are promising candidate susceptibility factors.Aim: BDNF rs6265 functional polymorphism was analyzed in order to determine its possible association with pediatric headache and migraine risk.Methods: The research included 120 consecutive pediatric patients who were diagnosed with headache and 120 healthy controls. The diagnosis was in compliance with the International Classification of Headache Disorders. Blood samples were collected from all participants and genotyped for rs6265.Results: BDNF rs6265 was significantly associated with decreased headache risk, particularly in the dominant model [Odds Ratio, OR (95% confidence interval, C.I.): 0.47 (0.26-0.85), p = 0.011] and the log-additive model [OR (95% C.I.): 0.48 (0.28-0.82), p = 0.0053]. During the sensitivity analysis, the associations were also maintained among patients with migraine.Conclusions: This is the first study to reveal a significant association of this BDNF variant with headache risk. Additionally, Val66Met was also for the first time related to decreased childhood migraine risk.