Contributo alla conoscenza della distribuzione degli antigeni dei sistemi ABO, MN, Rh nella popolazione del Lazio

Abstract

SummaryIt has been the intention of the Authors to make a contribution to the study of the distribution of the blood groups ABO, MN and Rh among the population of the region of Lazio. A report is made on the results of 1042 blood-group tests carried out on subjects living in the region under consideration, no account beeing taken of their ethnic origins.The data observed have been studied to establish the phaenotype frequency, and to ascertain the proportion of the genes (by making use of the methods based on the criterion of « maximum likelihood »). The χ2 test was also used to make a comparison between the diHe-rent ascertainments.In 502 subjects out of the 1042, the serum was examined for the presence of the antigen « e » which, in fact does not occur very often.A comparison was made between the sample of the population observed and the results with the same criteria in the choice of the subjects. A comparison with similar investigations carried out by other Authors in the region of Lazio has been possible in the case of the ABO and MN blood groups, while for the Rh group there are comparable investigations only for the provinces of Milan and Pavia.The composition of the samples examined has shown some differences which have been evaluated by making use of the most appropriate statistical method. The χ2 test enables us to establish, on the basis of the number of degrees of liberty, what the frequency is of the samples whose representative point is more than χ away from the representative point of the sample chosen as a model. If this frequency is below a certain figure, for example 0.05, we may conclude that the empirical sample is a rare one for the distribution chosen as a model; and this divergence is attributed predominantly to systematic factors, since the empirical distribution is a sample corrisponding to another population.The present population of the region of Lazio, as appears from the researches under examination is at the limits of homogeneity for the distribution of the principle types of the ABO groups: it is difficult to come to a con-elusion concerning the significance of the variation in the frequencies observed by different Authors. In the case of MN group the hypothesis of homogeneity is admissible, but the respective data for the region are as yet too meagre. A comparison between the different populations has given negative results for homogeneity in the case of Rh group.Differences in results among investigations carried out in the same region must be attributed not only to the criteria of choice of the subjects examined (these also may not be a representative sample of the population), but also in the incomplete ethnic homogeneity of the individuals chosen. This is important for the purposes of anthropology, while for the purposes of forensic medicine it is useful to have a classification of the present population independently of the grouping according to ethnic origin. The frequency rate of blood groups can be evaluated by considering the average of the results of numerous investigations, provided that these are similar to each other at least in part. The percentage figures, taken out of all the investigations made in the region compared with each other, are the following; group A = 39,44%, group B = 11.44%, group AB = 3.98%, group O = 45.14%, group M = 33.09%, group N = 17.73% and for group MN = 49.18%.