Radiologic anthropometry of the hand in patients with familial short stature.

Fifth metacarpal bone shortening (brachymetacarpia V) was recently described to be highly prevalent in children with familial short stature (FSS). To characterize the hand bones of FSS patients with and without brachymetacarpia V, the left hand bone age radiographs of 26 FSS children were reviewed. In 16/19 patients with clinical brachymetacarpia V radiographs revealed fifth metacarpal bone shortening with a gap of 2 mm or more between the distal end of the fifth metacarpal bone and a tangential line connecting the distal ends of the third and fourth metacarpal bones. Only one of 7 patients without clinical brachymetacarpia V had a gap of 2 mm. Radiologic anthropometry revealed that FSS patients with clinically shortened fifth metacarpal bone frequently had shortened first metacarpal bones, second and third proximal phalanges, and fifth distal phalanx as well. FSS patients without clinical fifth metacarpal bone shortening had shortened third and fourth metacarpal bones, fifth proximal phalanx, and fifth distal phalanx. Fifth metacarpal bone shortening was only detected clinically if the fourth metacarpal bone was not short as well. Reduction in height correlated more with reduction in metacarpal bone length than with that of the other hand bones. These peculiar tubular bone alterations commonly seen in FSS suggest a disturbance in endochondral ossification, the process primarily involved in tubular bone elongation.