Only the most common variants for α+-thalassemia (-α3.7and -α4.2) and α0-thalassemia (--MED and --SEA) are shown for each region. The variants that appear in parentheses are those for which the data used to make this map are limited.
© 2014 Massachusetts Medical Society. From the New England Journal of Medicine, Piel FB and Weatherall DJ, ‘The α-Thalassaemias’, 371(20), 1912. Reprinted with permission from Massachusetts Medical Society.