[Reinhardt-Pfeiffer mesomelic dysplasia or dyschondrosteosis? Is the distinction well-founded? Apropos of a familial case with variable expression].

A familial observation of Reinhardt-Pfeiffer type mesomelic chondrodysplasia spanning three generations is reported. This case clearly shows that expression of the disease can vary widely within a given family. One member affected as a fetus had a severe form suggesting Langer mesomelic dwarfism syndrome, whereas his mother was free of clinical symptoms and his maternal aunt had a typical form of Reinhardt-Pfeiffer syndrome. Clinical manifestations in the other affected family members were perfectly consistent with dyschondrosteosis syndrome. The very broad spectrum of clinical patterns in this family suggests that there may be connections between the various types of mesomelic dysplasia. Establishing clear-cut distinctions between these entities, although useful in practice, may not accurately reflect molecular anomalies. Furthermore, the family member affected as a fetus also had Turner syndrome, which may have contributed to the severity of his condition. The possibility of identifying severe mesomelic dysplasias antenatally by ultrasonography should be pointed out.