Seciion 15 — Human Genetics 



A-2740 (Hema) from the U.S.A. Public Health 

 Service and R/00014 from the World Health 

 Organization. 



15.24. The Problem of the Associations Between 

 Blood Groups and Disease. Angelo Cresseri 

 and Angelo Serra (Milan, Italy). 



It has been frequently stated that research 

 on the associations between blood groups and 

 disease would have ensured an important con- 

 tribution to the understanding of the workings 

 of natural selection, and given the chance of 

 opening up new methods of research on impor- 

 tant diseases. 



Of course both are goals that suppose (1) a 

 detailed knowledge of all the blood groups of a 

 given system effectively associated with a partic- 

 ular disease, and of what is the degree of asso- 

 ciation; (2) a definite demonstration of the 

 constancy of the phenomenon of the association 

 between blood groups and a disease. 



With a view to get consistent information on 

 these to fundamental points, an analysis has 

 been done — according to classic models and 

 with the help of an electronic computer — of 

 most published data since 1953. 1162 samples 

 in all were analysed; 115 of them ought to be 

 excluded, because the frequency distribution of 

 the blood groups in the control subsamples 

 deviated significantly — the significance level 

 having been fixed at the probability point 

 0.01 — from that expected in the hypothesis of 

 panmixia, thus suggesting non-randomness in 

 the sampling. The other 1057 samples are un- 

 evenly assignable to 273 diseases; subdivisions 

 by age, sex and clinical criteria increase up to 330 

 the independent classes. 



The detailed results will be published else- 

 where. A few general conclusions seem worthy 

 to be outlined here. 



(1) No clear-cut statement, relevant to the 

 two fundamental points mentioned, may at 

 present be done for the majority of the diseases 

 studied up tonow, because of scarcity of samples 

 available for the analysis. 



(2) The relative risks of morbidity of given 

 blood groups, estimated from various samples 

 of the same disease, are often significantly he- 

 terogeneous, even though either each one or 

 most of them deviate significantly from unity as 

 the combined estimate also does. That happens, 

 for instance, for the risk A : O in the cases of 

 gastric cancer (58 samples), peptic ulcer (35 sam- 

 ples), duodenal ulcer (31 samples ) and of the 

 cancer of uterus (cervix) (16 samples). This 

 fact would suggest that, when the existence of 



a peculiar association may be considered as 

 statistically proved, one should take in account 

 also the possibility that systematic factors af- 

 fect differently the degree of correlation. 



(3) Many more researches at the biometric 

 level are still highly desirable, in order to reach 

 reliable and meaningful conclusions. 



15.25. The Genetics of Insensitivity to Pain: Studies 

 on Two Families. N. Leon, W. Becak:, M. L. 

 Becak:, B. J. Schmidt, F. Ottensooser and 

 P. H. Saldanha (Sao Paulo, Brazil). 



Congenital analgesia is a very rare disease. 

 About sixty cases have been reported in pertinent 

 literature but its etiology seems rather obscure 

 mainly because of the variable expressivity of the 

 disease. Most propositi are sporadic cases which 

 are identified by their indifference to painful 

 traumatisms. They frequently have sequels of 

 bone fractures and tongue cuts. Both sexes seem 

 to be equally susceptible and occasionally 

 members of the same sibship present the same 

 condition. The parents of the affected subjects 

 are frequently normal and sometimes consan- 

 guineous. 



Two families, including various members with 

 congenital analgesia have been examined. Both 

 families live in country towns of the State of 

 Sao Paulo. In the first family, the propositi are 

 children of normal and unrelated parents. The 

 sibship is represented by 8 living and two de- 

 ceased sibs. Two brothers, 8 and 2 years of age, 

 are affected, one of them suffering from bilateral 

 cryptorchidism; a third affected brother died 

 with six months of age. A girl belonging to the 

 same sibship has heterochromia iridis and a 

 cousin of the propositi, on the paternal line, has 

 club foot. 



The second family includes ten living and one 

 deceased sibs. Two of them, 6 and 1 1 years 

 old, present analgesia. The parents of the propo- 

 siti are normal and display multiple consan- 

 guinity ( / = 0.0703). It is noteworthy that the 

 father is the only son in a sibship of 1 1 indivi- 

 duals. Cleft palate occurred in two cousins of the 

 propositi. 



It should be emphasized that in the two fami- 

 lies examined, the parents are normal, one of 

 the families presenting a high inbreeding coef- 

 ficient. The rate of normals to affected members 

 in both families is 5 : 16. These findings suggest 

 recessive monogenic inheritance. 



The ABO, MN, Rh blood groups and sali- 

 vary secretion have been analysed in all members 

 of both families. No close linkage between these 

 "markers" and analgesia congenita is apparent. 



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