Alpha-1-antitrypsin deficiency in the Cape Verde islands (Northwest Africa): High prevalence in a sub-Saharan population

Alpha-1-antitrypsin (AAT) deficiency results from mutations on the Protease Inhibitor (PI) locus located in chromosome 14 and has been associated with pulmonary early-onset emphysema and chronic obstructive pulmonary disease (COPD). African populations show a lower prevalence of AAT deficiency compared to Europeans.

Two hundred and two (202) unrelated samples from the Cape Verde archipelago (Northwest Africa) were genotyped for the two most common AAT deficiency alleles, PI*S and PI*Z, using PCR – Mediated Site-Directed Mutagenesis.

PI*S mutation in Cape Verde (3.2%) presents one of the highest frequencies in sub-Saharans, similar to South Africa (3.3%) but lower than Angolans (18.8%), Namibians (14.7%), Nigerians (6.4%) and Botswains (4.5%). The PI*Z mutation shows lower values (0.2%) than other sub-Saharan populations, namely Somalia (1.15%), Mali (0.98%)or Nigeria (0.36%). However, many other sub-Saharan populations, like Botswana, Congo, Cameroon, Angola, Gambia, South Africa, Mozambique and Namibia, lack the PI*Z mutation.

The frequency of all the AAT deficiency genotypes in the Cape Verde archipelago (PI*ZZ, PI*SS, and PI*SZ) was estimated to be one of the highest in sub-Saharans (15 per 1000), only lower than Angola (54 per 1000) and Namibia (22 per 1000).

The results obtained show a high prevalence of the AAT deficiency in Cape Verdeans when compared to other sub-Saharans a condition that can be explained by a heavy European genetic influence, characteristic of that population.