AN AUTOPSY CASE OF ACHONDROPLASIA IN ONE OF BINOVULAR TWINS OF DIFFERENT SEX

An achondroplastic female newborn in one of binovular twins of different sexw as reported. The incidences of this peculiar dwarfism were also reported, which were based on the delivery records in our clinic for the recent 5 years and on the statistics of over 90,000 autopsy cases in Japan from 1958 to 1964. Neither apparent hereditary factor nor contributory clinical history of their parents was detected. The autopsy of the twins revealed that the female infant was a typical achondroplastic dwarf associated with pulmonary hypoplasia and hypoplasia of the endocrine organs, and that the male infant was a nonachondroplastic premature baby of 8 months gestation, who died of respiratory distress due to hyaline-like membrane. Histochemical findings of the ground substance of the cartilages, fixed by different fixatives, of both cases were compared. After formalin fixation, in the abnormal cartilages of the achondroplastic acid mucopolysaccharide diminished distinctly. After ethanol fixation, however, much of the acid mucopolysaccharide was retained. The histochemical tests suggested that the intense reactions in the ethanol-fixed materials would be due to the presence of chondroitin sulphuric acid A or C. Therefore, chondroitin sulphuric acid in the achondroplastic cartilage might not be bound with protein of the ground substance.