Section 15 — Human Genetics 



normal). It is highly improbable that these, 

 apparently fibrous stiffness, is related to the 

 syndrome. We have to take account of a possible 

 recessive transmission of a mutated gene. The 

 most common form of hereditary deafness is a 

 recessive one. Splithand and foot nearly always 

 follows a dominant mode of transmission, only 

 very few (doubtful) recessive cases are known. 

 The incidence of recessive deafness in Holland is 

 1 : 5000, splithand and foot occurs in 1 : 100,000. 

 These figures make it highly improbable that 

 the association of the two abnormalities is 

 fortuitous. Being an exogene causation of the 

 occurring together of the two anomalies in two 

 brothers highly improbable, I think the most 

 reasonable explanation is a rare recessive gene 

 giving rise to the syndrome. Only Birch Jensen 

 saw one sporadic case and an inquiry to the 

 other institutes for the deaf in Holland did not 

 reveal any more cases. 



15.53. Inherited Multiple Neoplasia Syndrome. 

 Eldon J. Gardner (Logan, U.S.A.). 



A syndrome including multiple or diffuse in- 

 testinal polyposis, osteomas, fibromas, epidermal 

 cysts, and dental anomalies, has been investigated 

 over a period of 15 years in a Utah family group. 

 The most serious aspect from the standpoint of 

 the family under consideration was the polyposis, 

 known to predispose to carcinoma of the colon 

 and rectum. 



When the study began in 1948, carcinoma 

 originating in the lower digestive tract had been 

 the cause of eight deaths among the descendants 

 of one woman. All 51 living descendants of the 

 woman were examined. Six were found to have 

 intestinal polyposis and other manifestations of 

 the syndrome. 



Two cases of fibrosarcoma have been added 

 to the list of manifestations in people who 

 evidenced other aspects of the syndrome. While 

 the family members have been under observation, 

 two children have developed multiple polyposis 

 and five others have expressed epidermal 

 cysts and/or fibromas. These latter types of 

 lesions appear earlier in life than intestinal 

 polyps and therefore serve as diagnostic traits for 

 identifying children who may be expected to ex- 

 press the more serious aspects of the syndrome 

 later in life. 



Among the children who have lived long 

 enough to be identified as having or not having 

 the syndrome and who had one parent who 

 expressed the syndrome, 20 were positive and 

 16 were negative. This observation is not 



significantly different from the 1 : 1 ratio expected 

 in cases of single gene dominant inheritance. 



15.54. Neoplastic Diseases in Twins. Richard H. Os- 

 borne and Frances V. Degeorge (New 

 York, U.S.A.). 



This first report of a comprehensive study of 

 twins in the hospital and clinic populations of the 

 Memorial Sloan-Kettering Cancer Center, New 

 York, will introduce the methodological pro- 

 blems inherent in twin-cancer studies, and 

 present the variable distribution of twins in 

 this patient population. 



In theory twin studies constitute a simple and 

 an effective method for investigating the human 

 cancer problem. In actual practice, however, it 

 is found that the application of a standard twin 

 study method results in untenable assumptions 

 concerning the probable nature of human 

 cancer. The variable distribution of 166 twin- 

 born patients in different benign and malignant 

 diagnostic categories relative to that of single- 

 born patients demonstrates the unique nature of 

 the twin-cancer problem and the possibilities 

 offered by twin study methods for investigating 

 neoplastic diseases. 



15.55. Genetic Factors in Hypophysial Tumours. 

 H. Hamlin (Boston, U.S.A.). 



A statistical relationship between O and A 

 blood group genes and chromophobe adenoma 

 of the pituitary has prompted search for genetic 

 determinants in other types of hypophysial 

 tumor. There is the chromophil (eosinophil) 

 adenoma that produces the extraordinary 

 clinical condition of acromegaly; also the pitui- 

 tary giant, usually associated with a mixed type 

 of chromophobe and chromophil hyperplasia. 

 Such abnormally overgrown specimens of 

 humanity are counterpoised by the unique 

 pituitary dwarfs who are usually well-proportion- 

 ed physically and often superior mentally. 

 Genetic factors are strongly suggested in the 

 hypophysial duct tumor (craniopharyngiona) 

 because of its clearly established patho-embryo- 

 genesis. Experimental data is cited to suggest that 

 estrogen-induced pituitary adenomata have 

 shown genetic linkage in certain Fi-hybrid mice 

 strains. Examples of human hypophysial neo- 

 plasia are presented to indicate that constitution- 

 al factors should always be suspected in these 

 disorders. 



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