The ‘Hot Spot’ of Hb E [β26(B8)Glu→Lys] in Southeast Asia: β‐Globin Anomalies in the Lao Theung Population of Southern Laos

Abstract

Hb E [β26(B8)Glu→Lys], is the most common abnormal hemoglobin (Hb) in Southeast Asian populations. The hitherto highest frequencies of the Hb E gene (HBB*E) in large population samples, ∼ 0.3, were observed in the southern part of northeastern Thailand. The finding of even higher frequencies in a small, isolated Austroasiatic group in Northeast Thailand prompted us to examine samples of three Austroasiatic populations in southern Laos (official designation: Lao Theung), an area inhabited by numerous ethnic groups belonging to the Mon–Khmer branch. Blood samples were collected from a total of 603 adult subjects. The HBB*E frequencies were 0.426 in the So of Khammuan Province, 0.433 in the Alak/Ngeh of Sekong Province and 0.253 in the Oy of Attapeu Province. The HBB*E frequencies in the So and Alak/Ngeh are the highest observed in Southeast Asia in representative population samples. None of the common Southeast Asian β‐thalassemia (thal) mutations were found. The results are discussed with respect to natural selection by malaria, selection time, effects of β‐thal and the ethnic history of the population of Southeast Asia.