HEREDITY OF TUMORS OF THE NERVES 



Another Alleged Mendelian Dominant in Man 



DK. SAMUEL A. PREISER of 

 Montefiore Home and Hospi- 

 tal, New York, and Dr. Charles 

 l). Davenport of Cold Spring 

 Harbor, N. Y.. have published in the 

 American Journal of Medical Sciences, 

 for October, 1918. some evidence, in- 

 terpreted by them to mean that the rare 

 disease, known as multiple neurofibro- 

 matosis (von Recklinghausen's dis- 

 ease), is inherited as a Mendelian 

 dominant. 



"Among the rarest of abnormal con- 

 ditions of the surface of the body is 

 that characterized by a large number 

 of sessile or pedunculated swellings or 

 tumors, sometimes soft and elastic, 

 sometimes firm and tough, that vary 

 in size from that of a millet-seed to 

 that of a child's head. The skin over 

 the tumors is frequently discolored, 

 brownish or bluish, or redish through 

 enlarged capillaries. They may be pres- 

 ent from birth and they may tend to 

 grow, usually very slowly, but they 

 rarely, if ever, regress in size. Exami- 

 nation shows that they are fibrous tu- 

 mors, frequently containing one or 

 more nerve fibers ; or, wlien more deep- 

 seated, being enlargements of the peri- 

 neurium of the nerve trunks. They are 

 due to localized cell proliferation of the 

 connective-tissue sheaths of the nerves. 

 "The number of these nodules varies 

 with age and constitution of the indi- 

 vidual. They tend to increase in num- 

 ber, as well as in size, with age. At 

 one extreme there may be only a soli- 

 tary growth uix)n one nerve, at tiie 

 other the number is verv great. Thus, 

 Robert Smith (1849) counted 450 on 

 one limb anfl over 2.000 on the whole 

 bofly. Octerlong (1875) counted 2,?>i^ 

 tumors on a negress of sixty-six years 

 and the count did not include some of 

 the smaller ones. Rut the record of 

 patience in counting seems to be held by 

 Hashimoto (1890). who made out 4.50.^ 



.^80 



tumors on the skin of a middle-aged 

 Japanese man. 



"Multiple neurofibromatosis is a rare 

 condition, as it is found in only about 

 1 in 2,000 cases that present themselves 

 to medical clinics or private practi- 

 tioners for skin diseases. No doubt 

 tliere are many alxirtive cases which 

 never get into the literature, but. even 

 so. the proportion of tHe population 

 which has the classical symptoms of 

 neurofibromatosis is very small. Des- 

 pite this there are many cases in the 

 literature of two to six members of a 

 family — blood relatives — who show 

 some of the symptoms. The frequent 

 concurrence of these relatively rare 

 symptoms in several mem1>ers of one 

 family cannot be accidental. It must 

 be due either to the presence in the 

 family of internal factors tending to 

 induce the symptoms or to external 

 agencies (such as contamination, ger- 

 minal infection) which act upon indi- 

 viduals (like those of a family) who 

 are in intimate contact. The fact that 

 only blood relatives are aflFected speaks 

 strongly against the contact hypothesis. 

 The possibility of an infection through 

 the germ cells cannot be denied. It is 

 to be noted, however, that father and 

 child are quite as often affected in the 

 same way as mother and child. This 

 proves that the tumors do not belong 

 to the class of diseases that are in- 

 duced merely by infection through the 

 placenta. 



"Though so many cases arc on record 

 of more than one afi'ected person in a 

 family, it is not to be overlooked that 

 in very many reports no mention is 

 made of relatives wlio have similar 

 symptoms with the patient ; also, there 

 are a number of cases in which the ex- 

 istence of affected relatives was denied. 



".An apparent cjifficulty in the way of 

 the hyuothesis that multiple neurofibro- 

 matosis is a <lomin;nU trait seems to He 



