Document Type



There is evidence that the CCR5- 32 mutation confers protection against HIV-1 infection to homozygous individuals. It is believed that this mutation spread through Europe with the Vikings and that it has been subjected to positive selection, leading to a high frequency in Europe ( 10%). We carried out the present study to determine the 32-bp deletion allele and genotype frequencies of the CCR5 gene (CCR5- 32) in the Atlantic island populations of Madeira, the Azores, Cabo Verde, and Sao Tome e Prı´ncipe. These Atlantic archipelagos were all colonized by the Portuguese in the 15th and 16th centuries, but the latter two received most of their settlers from the West African coast. The frequency of the CCR5- 32 mutation varies between 0% in Sao Tome e Prıncipe and 16.5% in the Azores. The Azores Islands have one of the highest frequencies of homozygotes found in Europe (4.8%). There are significant differences (P 0.05) between some of these populations, for example, between Sao Tome e Prıncipe and Cabo Verde, and even within populations (e.g., Portugal,Madeira, and the Azores)