Alpha 1-antitrypsin phenotypes in a Nigerian population.

Alpha 1-antitrypsin phenotypes of 350 normal Nigerian blood donors were determined by isoelectric focusing in polyacrylamide gel. The distributions obtained (MM, 66.86%; MS, 16.29%; MZ, 0.57%; SS, 2.0%; SZ, 0.28%) were different from those reported for caucasian populations. Forty-nine of these donors could not be classified into any of the above common phenotypes suggesting that some rare alleles occur in Nigeria. The probable cause and implications of the high frequency of the S gene in the Nigerian population are discussed.