A familial observation of hypophosphatemic rickets with unusual inheritance and 
evolution, different from that of X linked hypophosphatemia, is reported. The 
mode of inheritance was autosomal dominant, a father and his son being affected. 
Severe early signs of rickets and delayed growth were present in both cases. 
Plasma 1,25 dihydroxyvitamin D and PTH levels were normal. There was no 
hypercalciuria. Complete cure of rickets and catch-up growth were obtained with 
the only treatment of vitamin D (40,000 U/day) in the father and of 1 alpha 
hydroxyvitamin D (1 microgram/day) in the son. This observation is quite similar 
to the 'autosomal hypophosphatemic bone disease' described by Scriver et al. It 
illustrates the heterogeneity of familial hypophosphatemia which presently 
includes 4 different physiopathological entities.