[Hereditary pseudovitamin-D-deficiency rickets with alopecia as a consequence of extreme resistance of target organs to 1.25-(OH)2-cholecalciferol. Therapeutic progress in another disorder of vitamin-D-metabolism (author's transl)].

We report about a pair of Turkish siblings suffering from alopecia and severe rickets. In the elder sister we could show the causal role of extreme resistance of target organs to 1.25-(OH)2-cholecalciferol. The birth of a brother who developed the same symptoms together with two other similar cases in siblings recently published by other authors, made it possible to recognize the disorder as a typical syndrome-like entity, based on a hereditary defect. By successful administration of excessive (and so-far not previously published) doses of Vitamin-D3 a way for therapeutic progress in this new type of vitamin-D-dependent rickets is shown.