Association of Brain Derived Neurotrophic Factor (BDNF) rs6265 Gene Polymorphism With Susceptibility to Epilepsy

Overview

Epilepsy is a common neurological condition that affects people of all ages.Recent studies found that epilepsy is associated with several chromosomal regions, where mutations in these regions cause neurological dysfunction. BDNF which is the most ample neurotropic factor in the CNS, has survival and growth promoting roles in a variety of neurons. It has been shown to promote excitatory (glutamatergic) synapses while weakening inhibitory (GABAergic) ones. A nonsynonymous G to A single-nucleotide polymorphism (SNP) exists at position 196 of exon 2 (rs6265), which results in valine (val) to methionine (met) substitution. This polymorphism affects intracellular packaging of pro-BDNF, its axonal transport and in turn, activity-dependent secretion of BDNF at the synapse.

Epilepsy was defined as the separate occurrence of two or more unprovoked seizures, manifested by involuntary motor, sensory, or autonomic, alone or in combination, and not diagnosed as neonatal or febrile seizures. Despite extensive studies, the molecular causes of the disease are not yet discovered completely. A functional imbalance between excitatory (transmitted by glutamate) and inhibitory signals (transmitted by γ-amino butyric acid or GABA) in neural cells has been regarded as a putative contributing factor in epilepsy. The brain-derived neurotropic factor (BDNF) encodes a small dimeric protein which is the most ample neurotropic factor in the CNS.It has been shown to promote excitatory (glutamatergic) synapses while weakening inhibitory (GABAergic) ones.Any interference with the BDNF signaling pathway may negatively affect downstream neuronal functions and cause neuronal diseases. A nonsynonymous G to A single-nucleotide polymorphism (SNP) exists at position 196 of exon 2 (rs6265), which results in valine (val) to methionine (met) substitution at codon 66 (val66met), changing the 5' proregion of the human BDNF protein. This polymorphism affects intracellular packaging of pro-BDNF, its axonal transport and in turn, activity-dependent secretion of BDNF at the synapse

Conditions