The Brain-Derived Neurotrophic Factor Val66Met Polymorphism Is Associated With Female Obsessive-Compulsive Disorder: An Updated Meta-Analysis of 2765 Obsessive-Compulsive Disorder Cases and 5558 Controls

A study of serum brain-derived neurotrophic factor level in individuals with obsessive compulsive disorder and their first-degree relatives as compared to the healthy population

Background

The nosological tradition in psychiatry defines diagnostic criteria for disorders based on expert consensus than objective biological markers reflecting underlying neurobiological correlates. Endophenotypes have been researched as heritable biological markers that can be quantified and defined to represent intermediate measures of a psychiatric illness. In obsessive-compulsive disorder (OCD), various putative biomarkers such as neuropsychological, neurophysiological, neuroradiological, brain-derived neurotrophic factor (BDNF), etc., have been explored.

Aim

The study aimed to compare levels of serum BDNF in individuals with OCD and their unaffected first-degree relatives (FDR) with healthy controls (HC).

Methods

This cross-sectional study compared serum BDNF levels in medication-free/naive individuals with OCD (n = 30) to their FDR (n = 30) and age-sex matched HC (n = 30). Intergroup comparison was done using analysis of variance (ANOVA) and post-hoc Tukey's test. Correlation analysis was conducted to find the relationship of sociodemographic and clinical correlates to serum BDNF as well as dimensional subtypes of OCD.

Results

No significant difference in BDNF levels was observed between OCD and HC (P = 0.13) but a significantly higher level was found in the FDR group compared to age-sex matched HC (P = 0.02).

Conclusion

BDNF levels may have a complex interplay influencing the genetic inheritance and clinical manifestations of OCD. Further research is required before considering it a viable biomarker.

New Frontiers in Neurodegeneration and Regeneration Associated with Brain-Derived Neurotrophic Factor and the rs6265 Single Nucleotide Polymorphism

Brain-derived neurotrophic factor is an extensively studied neurotrophin implicated in the pathology of multiple neurodegenerative and psychiatric disorders including, but not limited to, Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, traumatic brain injury, major de-pressive disorder, and schizophrenia. Here we provide a brief summary of current knowledge on the role of BDNF and the common human single nucleotide polymorphism, rs6265, in driving the pathogenesis and rehabilitation in these disorders, as well as the status of BDNF-targeted therapies. A common trend has emerged correlating low BDNF levels, either detected within the central nervous system or peripherally, to disease states, suggesting that BDNF replacement therapies may hold clinical promise. In addition, we introduce evidence for a distinct role of the BDNF pro-peptide as a biologically active ligand and the need for continuing studies on its neurological function outside of that as a molecular chaperone. Finally, we highlight the latest research describing the role of rs6265 expression in mechanisms of neurodegeneration as well as paradoxical advances in the understanding of this genetic variant in neuroregeneration. All of this is discussed in the context of personalized medicine, acknowledging there is no “one size fits all” therapy for neurodegenerative or psychiatric disorders and that continued study of the multiple BDNF isoforms and genetic variants represents an avenue for discovery ripe with therapeutic potential.