It has been speculated in an online forum that Gs129 pertains to the uncommon O303 (previously known as O2) type. Apparently the 23andme chip has some difficulty in making accurate calls for O303, perhaps especially when it is combined with a B101 allele.
I have gs129 and it is confirmed that I'm B+, B/O. I have the B1O1/O3O3 alleles.
- The release of the 23andMe V4 chip may also be influencing this. I think until we have phased data, calling blood type remains impossible for some of the hard cases. --- cariaso 02:12, 20 February 2014 (UTC)
Oddly enough, I don't get Gs129. It would be better if I did, because Promethease's "guess" as to my blood type is actually just wrong. It predicts A, while I actually have type O. This has been serologically determined on more than one occasion, with never any difficulty. In fact, the first time my blood was ever typed, I did it myself in a university physiology class. Both of my parents were type B, and they thought I was, too. I was convinced I was doing the something wrong! But not only did the Red Cross later confirm that I was type O, when I gave blood for the first time, I could not have been type A with two type B parents. One sister of mine is also type O, while are remaining four siblings are type B. My daughter is also type O. Promethease predicts all three of us as type A, even though neither of our alleles is actually "rare". My sister, my daughter, and I all have O112 and O303.
O303 may be somewhat unusual in that it does not have the deletion at rs8176719 and instead has a "T" at rs41302905, but it is actually considered one of the six "most common" ABO alleles. Unlike Promethease, 23andMe has no difficulty in predicting my blood type.
People who believe they have the combination B101/O303 should revisit their data. Whereas 23andMe probably had been reporting rs41302905 as TT for them, they are now likely to find it has been changed to CT.
My mother is gs132 A101/O303(23andme) my brother and I are gs129 (can't be predicted but speculated type B) my husband is gs135 B101/O112 (23andme) our daughter is gs131 B/B and son gs129 & gs130 A/B. I have a daughter from a previous relationship and she is gs135, she was blood typed as a baby and was A/B but she show on 23andme to be B/O (B101/O112). The only way I can see one child with B/B and one with A/B while my husband is B/O is Cis-AB but I know that is exceedingly rare... How can my one daughter inherit a B/B while my son A/B plus the O303 allele with gs129? Does that mean he inherited A/B & O also know as Cis-AB? My daughter from a previous relationship (fathers blood type unknown) is A/B in medical records, gs135 on Promethease and B101/O112 on 23andme so that doesn't narrow it down either. Any thoughts?