SNPs in the SNAP25 gene were initially [PMID 17160701] linked to intelligence but have failed to replicate [PMID 19418213].
While now suspect, the original work can be found in [PMID 16801949].
The (T;T) genotype averages several PIQ points higher than the (C;T) genotype, which averages several PIQ points higher than the (C;C) genotype. [PMID 17908175]
For SNPs rs363039 - rs363043 - rs353016, respectively, the haplotype C-T-T is most associated with higher intelligence in children, whereas the haplotype C-C-T is most associated in adults (SNPs oriented as in dbSNP). [PMID 17908175]
[PMID 21497654] SNAP-25 single nucleotide polymorphisms are associated with hyperactivity in autism spectrum disorders.
[PMID 23593184] DNA variation in the SNAP25 gene confers risk to ADHD and is associated with reduced expression in prefrontal cortex.
[PMID 25024311] Possible association between SNAP-25 single nucleotide polymorphisms and alterations of categorical fluency and functional MRI parameters in Alzheimer's disease