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From SNPedia

The criteria are inadequate for predicting an A blood type.

If an individual has (rs8176746(G;G), rs8176747(C;C), and rs8176719 (D;I), he or she may in fact have two O alleles, instead of AO, provided that one of the O alleles is non-deletional. The non-deletional O allele O303 is sufficiently common to warrant consideration. O303, or ABO*O03 (O2), is one of "(t)he 6 common ABO alleles in white individuals", along with ABO*A101 (A1), ABO*A201 (A2), ABO*B101 (B1), ABO*O01 (O1), and ABO*O02 (O1v). (http://www.bloodjournal.org/content/102/8/3035?sso-checked=true)

To exclude this possibility, (rs41302905)(C;C) -- (rs41302905)(G;G) on the reverse strand -- should be added to the existing criteria.

(This is not hypothetical; I am in precisely this situation. I have (rs8176746(G;G), rs8176747(C;C), and rs8176719(D;I), which causes me to be predicted by Promethease as type A (AO). However, I also have (rs41302905)(C;T). My ABO alleles as predicted by 23andMe are O112 and O303. My blood type, as determined on multiple occasions through conventional serological typing, is O+.)

Thanks for the info. I've added ' not(rs41302905(T)) ' to the 'and', which I think will improve this, while allowing it to still showup if someone has no data for rs41302905.
That is however slightly different from your suggestion, in how it handles heterozygosity at rs41302905. How should a rs41302905(C;T) be called?
If you see it needing further help, I'm interested. email info@snpedia.com if you'd like some coupons for free promethease runs so that you can test it.
--- cariaso 20:34, 7 February 2015 (UTC)

This is good, I think; thanks. As far as I have been able to determine, the majority of those who do have rs41302905(C;T) probably have O303. Another non-deletional O might be possible, and in still-less-common situations, even perhaps a weak A. But compared to the other possibilities, O303 seems to be the most common. (See the link I posted above.)

Among other things, this means that if an individual has both rs8176719(D;I) and rs41302905(C;T), there is a probability that the individual will be type O (OO). One allele will be a more typical deletional O allele; the other will be a non-deletional O. Of course, it seems that will ABO alleles and blood type, there are always surprises.