Adult-onset vitamin D-resistant hypophosphatemic osteomalacia. A possible variant of vitamin D-resistant rickets.

A family of 133 members showing unusual manifestations of vitamin D-resistant hypophosphatemic osteomalacia was studied. The hypophosphatemic children did not have rickets or clinical femoral bowing: the hypophosphatemic young adults had minimum clinically evident femoral bowing; and the older adults (age forty and older) were progressively disabled by severe bowing. The disorder appears to be an X-linked dominant, with almost complete penetrance of the hypophosphatemic trait. The etiology of this disorder could not be determined.