Rare alleles of the ABO blood group system in two European populations.

We performed genotyping of the ABO system in Italian and Israeli population samples. The nucleotides at 11 positions, nts 261, 297, 467, 526, 646, 681, 703, 796, 802, 803 and 1060, were analyzed by PCR-RFLP, PCR-SSP and PCR direct sequencing methods. We found three rare ABO alleles besides the common alleles ()A1(Pro) (=()A101), ()A2(Leu) (=()A201), ()B (=()B101), ()O(T) (=()O01), ()O(A) (=()O02) and ()O2 (=()O03), but did not detect ( )A1(Leu) (=( )A102) which is a common allele in Asians. The rare alleles were tentatively named ()Ov1, ()Ov2, and ()Bv. As ( )Bv has been found in two Japanese individuals and ()O2 is not a rare ABO allele in Europeans, not only ()O2 but also the ()Ov1 and ()Ov2 alleles may be characteristic of European populations.