12 A NEW TYPE OF BRACHYPHALANGY IN MAN. 



way. That there must be here a marked variation in the somatic 

 appearance of the character seems indicated by the fact that one of 

 these affected members of the last generation is said to have had normal 

 parents. 



A very interesting case where brachyphalangy in some individuals 

 is combined with hyperphalangy, as in the cases just mentioned, is 

 reported by Vidal (1910), and extensively referred to and discussed 

 by Rabaud (1912). The record covers five generations, including 84 

 individuals. Two members of the third generation show the com- 

 bination of brachyphalangy with hyperphalangy and ankylosis. In 

 two individuals from the next generation only brachyphalangy is 

 present. One of these is interesting because the somatic type is very 

 much like the one here studied, the second phalanx of the index fingers 

 only being affected. In the other the second phalanx of the third and 

 fifth fingers are also brachyphalangous. 



Vidal does not try to bring his results in relation to the Mendelian 

 laws, and Rabaud uses his radiographs and records to prove that the 

 Mendelian heredity does not hold true for human material, since the 

 ratio between brachyphalangous and not-brachyphakngous individuals 

 in the offspring of affected family members is not in accord with the 

 theoretical expectation, and since the brachyphalangy which in some 

 cases behaves as a Mendelian dominant in others skips a generation. 

 Many family members are, however, described by Vidal as having 

 what he calls "doigt crochu" on one or on both hands, and these are 

 considered as "not brachyphalangous." A glance at the pedigree 

 shows that this is only another somatic manifestation of the character, 

 and in fact the most common one. The "doigt crochu" is shown by 

 19 individuals, while 11 are brachyphalangous. When both types are 

 counted together and considered as "affected," the ratio between 

 normal and affected individuals in the offspring of heterozygous indi- 

 viduals is very close to 1 : 1, the theoretical expectation. 



The case represents accordingly a very striking example of a dom- 

 inant malformation which manifests itself under very different somatic 

 types, a relation which can be explained through the assumption of 

 the presence of modifying factors. 



Cases in which the shortening affects metacarpal and metatarsal 

 bones are more frequently met with in the literature than the cases in 

 which principally the phalanges show the brachyphalangy. This 

 type is reported by Goldmann (1891), Kummel (1895), Roughton 

 (1897), Fontana and Vacchelli (1902), Sternberg (1902), Wagner 

 (1903-04), Hochheim (1903-04), Kenyeres (1905-06), Riedl (1907), 

 and others. The malformation generally affects one to three of the 

 metacarpse and metatarsse. The ulnar side seems most often to be 

 affected. The symmetry and vertical correspondence is not so marked 

 as in the cases discussed above, and since information concerning the 



