Distribution Of ABO And Rhesus D Blood Antigens In Morocco

摘要

To determine phenotypic and allelic frequencies of ABO Rhesus D blood groups in a Moroccans blood population, a sample 219 287 blood donors was collected from 15 different regions across the country. The overall ABO antigens frequency was 32.86%, 15.80%, 4.53% and 46.80% for blood groups A, B, AB and O, respectively. In addition, the Rhesus D positive frequency was 91.00%. The allelic frequencies found were 0.2089, 0.1078 and 0.6838 for A, B and O alleles, respectively, and 0.2999 for d allele. The regional distribution of the ABO blood antigens showed slight differences between the studied regions. However, statistical analysis of the regional allelic distribution of the D antigen was found highly significant (P> 0.001). A close analysis using a z- score test showed that Ouarzazate from the South East of the country clears apart from all other regions. These findings are concordant with the geographical and historical data of Morocco. Finally, the found distribution would be of a great help in mapping the country’s distribution of the ABO Rhesus D blood groups and blood donors’ population. Introduction The erythrocytic group systems have special significance in ethnical anthropology.1, 2, 3, 4 ABO and Rhesus blood group systems are the first human polymorphisms recognized at the molecular level.5 These polymorphisms have been widely used as genetic markers to study the characteristics of the populations.The distribution of these two blood groups has been repeatedly investigated in various populations all over the world during the last several decades and their frequencies exhibited considerable variation in different geographic locations, reflecting the underlying genetic and ethnic diversity of human populations.6, 7, 8, 9, 10, 11 Beside, many variations were observed in the distribution of blood type within human sub populations.12, 13, 14, 15Among the western Europeans, 42% belongs to A blood group, 9% to B blood group, 3% to AB blood group, and the rest, 46% to O blood group. However, some of the western Europeans show higher proportion (up to 40%) of the blood group B. On the other hand, pure American Indians belong almost exclusively to group O. Among white Americans, the frequency of group A is 41%, B is 10%, AB is 4%, and O blood group is 45%.16As it is noticed, the O blood type is very common around the world. About 63% of humans share it. Its highest frequency was found among the indigenous populations of central and South America where it approaches 100%. The lowest frequency, on the contrary, was recorded in Eastern Europe and central Asia, where B is common.12, 11The Rhesus system, on the other hand, is the most complex of all blood group systems with about 50 well established known antigens. Moreover, this system was heavily studied in the human population distribution. One of the major antigens of this system is the Rhesus D (Rh D). Its frequency varies from population to another. For example, about 85% of Caucasians and 95% of African-Americans are Rh D positive; whereas indigenous Africans are virtually all Rh D positive.17, 18Population genetics has made extensive use of this genetic marker (ABO blood groups). It seems that adjacent populations differ only slightly in the frequencies of particular genes and that these differences tend to increase with the distances separating populations.19Therefore, it is important to have information on the distribution of these blood groups in any population group.Morocco is a North African country. It has a population of more than 31 million and an area of 710,850 km2 (Annuaire Statistique du MAROC 2010), it spreads between Mauritania at the South and the Mediterranean sea in the North. The present gene pool of the Moroccan populations came from various origins as Berbers, Phoenicians, Sephardic Jews, Bedouin Arabs and sub-Saharan Africans.20, 21Only few uncompleted studies have been conducted in Morocco, especially the Rhesus D distribution. Beside, no study so far had