Yeah, I suppose I got the short end of the stick on this trade.
Knowing that dementia might be delayed by 7 years is worth quite a bit more than 3 milkshakes.
This is great news about other family members getting onboard.
You could work the genetics through.
With your sister's genetics, you might be able to determine your mother's genotype at rs1129844.
If your father genotyped, you could use an online tool to do a quasi phasing.
You might also be able to locate some other near relatives.
Perhaps you could even try something similar to my idea of using 23andme to find more distant relatives
to narrow down where the dementia risk variant might be.
In terms of actually getting this genotyped I am at a loss. I went to http://www.broadinstitute.org/mpg/snap/ldsearch.php
and chose all of the gene chips for rs1129844. None of them reported it!
I have made an inquiry about a special BGI has announced about a $250 50x exome sequence offer. That might be one of the
better bets. However, in our loved one's 65x exome scan the rs1129844 SNP happens right near the end of an exon and only has 10x coverage. Even at this coverage level we got a passing heterozygote call. Yet, if I were you, I would love to have 100x coverage for the SNP. Sometimes with these scans if they can scrimp a bit, they do. Often, they will have one big pile up near the middle of the exon and the coverage tends to become minimal or non-existent at the ends.
I have also asked a sequencer about individual SNP typing. The bean counting was $60 setup fee for each marker, $30 per marker genotyping by sequencing at 2x coverage using bi-directional Sanger sequencing PCR amplified with forward and reverse primer and
$28 per sample for saliva extraction. 2x coverage seems fairly weak, though Sanger sequencing is something of a gold standard. So, sure paying over $100 for a single SNP seems completely ridiculous, probably soon be able to get the entire exome done at high uniform coverage for that price, though the eotaxin SNP does seem especially important.