I recently uploaded one of the Autosomal DNA results I manage to GEDMatch.com and ran the X-Match routine and came up with a puzzling result.
The strongest result by far on the test has 37.2 shared X cMs length (as pictured below) but GEDMatch is reporting 0.00 Autosomal shared cMs with the same individual. My understanding is your total cMs are the combination of Total X and Autosomal cMs even though not X-cMs are not included in the total in all sites.
Both kits being compared are Male, though the two others with 0cMs on Autosomal are female.
X-DNA Result Only from GEDmatch.com
Note: Kit numbers have been excluded intentionally.
The key to reading the above graphic is here:
I emailed the person to confirm they uploaded their autosomal results also as well as try to determine if there is an immediately obvious shared ancestor, but have not heard back.
They have an "A" kit which implies they tested on Ancestry.com, which is contained as a single file and uploaded as a single file to GEDMatch, unlike ftDNA which is uploaded as X and Autosomal files. So I would think incomplete data is not the case.
I also read the Working with Autosomal Results question which in the answer stated "One other minor point of leverage in your situation: If you have a significantly-sized match on your X chromosome, that allows you to exclude your paternal grandfather's side (whether or not your half-sister matches). That is just a result of the normal rule of the X never going from father to son." which is what I was trying to determine which side an autosomal result was from when I came across this situation.
I also read ISOGG's articles on both how Autosomal scores are calculated (it is different between each site where GEDMatch allows you to score them the same way, such as ftDNA does not include X shared cMs in score) and working with X-Results but it is still not clear as how to interpret this situation.
I have also tried adjusting the minimum cM length all the way down to 4 and still nothing when doing a 1:1 with this kit on the Autosomal test. I have also looked at their "list" of matches and they have Autosomal matches with shared cMs but none on the kit I am comparing it to?
Has anyone experienced similar results and is there something else I am missing in its interpretation?