10 A NEW TYPE OF BRACHYPHALANGY IN MAN. 



some hereditary influence at work, but how it acts it is impossible to 

 say." The supposition of a dominant modifying factor, introduced 

 through the normal parents of these individuals, would account for 

 the occurrence of this special type, a point that is discussed to some 

 extent later in the present paper. 



Before leaving this group a case reported by Walker (1901) deserves 

 mention. He followed a case of complete bony ankylosis of various 

 joints between the phalanges, combined with brachyphalangy and 

 hypophalangy, transferred by the affected individuals through five 

 generations. The shortening was in nearly every instance most 

 strikingly observed in the middle phalanx. The hypophalangy, 

 absence of one or more bones of the little and ring finger, occurred in 

 some members of the fifth generation. This case accordingly repre- 

 sents another example of a dominant malformation of this class mani- 

 festing itself under different somatic types. 



A second group of brachyphalangy, less extreme than the one just 

 spoken of, is the one to which Farabee's case belongs. Here, too, we 

 have a very clear " pre-Mendelian " case, described by Kummel in 

 1895 (Fall xx), "Alle Finger haben nur zwei Phalangen." The second 

 row is described as being entirely absent. "Nichts auffallendes" was 

 noticed with regard to the feet, a statement to which not very much 

 importance can be attributed since radiographs are lacking. The 

 malformation of the hands is "auf das genaueste symmetrisch." 



Kummel investigated three generations and his pedigree including 

 more than 50 individuals, of which about 30 are affected (some uncer- 

 tain) clearly shows the features typical for the inheritance of a simple 

 Mendelian dominant. Kummel was fully aware of the fact that family 

 members who do not show the malformation have only normal children. 



The standard case of this type is that of Farabee (1905), who fol- 

 lowed the malformation through five generations including 33 normal 

 and 37 abnormal individuals, of which 3 were photographed and 

 radiographed. Farabee interpreted his case as one of "hypopha- 

 langia," "reduction in the number of phalanges." "One is hardly 

 justified in saying that one or the other segment is missing." But 

 Drinkwater (1908 and 1914-15) recognized, by means of his more 

 numerous radiographs, that the nature of the malformation is in 

 reality a very pronounced brachyphalangy of the second row of pha- 

 langes combined with a bony ankylosis of this rudimentary phalanx 

 with the terminal one. Farabee states that "in all cases hands and 

 feet were affected in exactly the same way." 



That the malformation can hardly have been as invariable as Fara- 

 bee's description seems to indicate may be concluded from Drink- 

 water's paper (1914-15). This author succeeded in proving that his 

 "second brachydactylous family" was an English line of the American 

 family studied by Farabee, one member having emigrated to England, 

 there giving rise to the family studied by Drinkwater. 



