About 1 in 1700 whites of northern European descent are homozygotes for this mutation and thus have plasma antitrypsin levels that are 10% to 15% below normal, he said.

• 北欧血统白人每1,700人有1人是此一突变的同合子， 因此血浆抗胰蛋白酵素值比正常低10%25到15%25。