To the Editor.—We are pleased to have had the opportunity of reading the interesting description by Kaufman et al1 of their clinical, histologic, and radiologic findings in a case of thanatophoric dwarfism. With respect to the spinal abnormalities observed in this form, we should like to draw attention to a feature noted by us in a recent case,2 namely, a small tongue of radiopacity extending about 3 mm from the anterior face of L-1. Since the roentgenograms published by Dr. Kaufman et al are all in anteroposterior projection, it cannot be seen whether or not this abnormality was present in their patient. In France, P. Maroteaux (personal communication, 1969) has also observed an example of this formation. We suggest that it may be taken into consideration as a characteristic, albeit inconstant, feature of thanatophoric dwarfism.