The “T” allele of rs1378810 in your DNAJC13 gene has been associated with a slight benefit (less than 0.4% variance) in general cognitive ability. You can check your 23andMe profile.* What? You’re a TT? Ooooh … nobody is impressed. But let’s not make light of our DNAJ genes just yet.
Consider the critical role of DNAJC5, a so-called cysteine-string protein (because it encodes a protein with an array of cysteine residues). This protein helps synaptic vesicles fuse and un-fuse so that your neurons can release and re-cycle tiny packets of neurotransmitters – which is how neurons send signals to one another. Yeah, vesicle fusion is really important … and is happening like a quadriillion times right now in your brain.
Mutations in the cysteine string of DNAJC5 have been associated with Huntington’s disease.
*Interpreting 23andMe data here can be confusing because 23andMe lists an A or T as possible alleles but one isn’t always sure which strand the research literature refers to and if that strand is the same strand that 23andMe is reading from. Luckily SNPedia points out that an rs1378810 TT is in tight linkage disequilibrium with rs2133692 TT (T or C alleles) so you can check this genotype on 23andMe to infer your rs1378810 genotype. My 23andMe profile says AA at rs1378810 and TT at rs2133692, so I think I have the slightly beneficial TT genotype … but I’m really not sure. Confused? Me too. But like the research suggests, this genotype really doesn’t add much to one’s general cognitive ability.