Met/Met (higher risk) variant of the Val66Met SNP in the BDNF gene that codes for brain-derived neurotrophic factor. Met/Met is associated in some (but not all) studies with slightly increased susceptibility to certain mental health disorders such as ADHD and depression.
[PMID 20042999] associated with introversion
This genotype may provide resistance to depression when subjected to repeated defeat blog summary
On a driving-based motor learning task subjects with this genotype showed greater error during short-term learning and poorer retention over 4 days, relative to subjects without the polymorphism. The presence of this BDNF polymorphism is associated with differences in brain motor system function, altered short-term plasticity, and greater error in short-term motor learning. [PMID 19745020]