Diego antigen system

red blood cells and, in a shortened form, in some cells in the kidney. The Diego^a antigen is fairly common in Indigenous peoples of the Americas (in both North and South America) and East Asians

transfusion reaction. Anti-Di^b usually causes milder reactions.^[2]

transfusion reaction. Anti-Wr^b is very rare, and little data is available on its severity.^[2]

blood serum from the mother. Rare blood types known at the time were eliminated, and the new type was classified as a "private" or "family" blood type. The investigators, with the agreement of the father, named the new type after his surname, "Diego". In 1955 investigators found that the Diego family included ancestry from Indigenous peoples of the Americas, and that the Diego factor (Di^a) was not restricted to the Diego family, but occurred in several populations in Venezuela and elsewhere in South America. Investigators suspected that the Diego factor might be a Mongoloid trait, and tested groups of Native Americans in the United States and people of Chinese and Japanese ancestry, and found Di^a in those groups. Anti-Di^b was found in 1967, establishing the Diego group as a two-antigen system. In 1993 the Diego pair of antigens was found to result from a single point mutation (nucleotide 2561) on what is now called the SLC4A1 gene on chromosome 17.^[1]

Kaingang people of Brazil was 49% Di^a+. Samples of other groups in Brazil and Venezuela were 14% to 36% Di^a+.^[2]

Waica people, and occurs at very low frequencies in the Warao and Yaruro people of interior northern South America. Layrisse and Wilbert, who characterize these people as "Marginal Indians", proposed that they are remnants of a first migration into South America of people who had not acquired the allele for the Di^a antigen, with other indigenous peoples of South America resulting from a later migration.^[6]

Aleut people (the incidence of Diego^a+ in Aleuts is comparable to South American levels), it occurs at a much lower frequency (less than 0.5%) among Alaskan Eskimos and has not been found in the Inuit of Canada.^{[8][9][10][11]}

Koreans, 7% to 13% Di^a+ for Mongolians, 10% Di^a+ for northern Chinese and 3% to 5% Di^a+ for southern Chinese.^[1][12]

ethnic Malays to be a little over 1%, and in ethnic Indians (descended from southern Indians) to be a little under 1%. (A smaller sample of Malays in Penang, Malaysia, were 4% Di^a+.)^[12]

Papuans, natives of New Britain, and Polynesians.^[11]