| Abstract: | A radiographic study was made of the left fifth medial phalanges of 200 Philadelphia Negro and 96 Chinese children. Twelve cases of abnormal shortening of this bone (defined, for the present, as less than half the length of the fourth medial phalanx) were found in the Chinese sample, while none were found in the Negroes. This trait, brachymesophalangy 5, in general seems to be characterized by short but well proportioned diaphyses and cone-shaped epiphyses with very early union. Population surveys reported in the literature indicate that this trait is considerably more common in Mongoloid and American Indian populations than in Whites or Negroes. The mode of inheritance of this genetic trait is uncertain, but present evidence indicates that it may be a simple autosomal recessive. |
