The first case of AB phenotype mutation found

The first case of "cis-AB09" has been discovered in South Korea. Children of parents who both have blood type B should normally have blood type B or O, but the discovery has shown a case of AB.

Co-research conducted by two groups of researchers, one led by Dr. Cho Duk of Samsung Medical Center and the other led by Dr. Shin Hee-bong of Sunchunhyang University Hospital, submitted a report on regarding the new case in the journal "Transfusion Medicine." Dr. Cho said that it was the first time a case of cis-AB09 was reported to an international blood bank. The person diagnosed with cis-AB09 was a 29-year-old woman who was blood tested for ovarian cysts surgery.

In a traditional AB phenotype, which account for 10-15 percent of all people, A and B antigenes are inherited separately from the father and mother while a cis-AB allele comes from one parent only. The cis-AB phenotype is numbered from cis-AB01 to cis-AB08.

The newly discovered cis-AB09 is a particularly rare case even in the cis-AB group. It is a mutation that has genes not related to either parent at all. Dr. Cho explains that a new set of genes that are totally different from the ancestors was created by mutation.

A cis-AB09 retainer cannot receive blood transfusion by an ordinary AB retainer, but must receive blood by the O group. The research team suggested that those with such rare blood types are recommended to have their own blood stored regularly.

noel@donga.com