[X-linked familial hypophosphatemic rickets report of six cases (author's transl)].

X-linked familial hypophosphatemic rickets (X.L.F.H.R.) is one of the D resistant rickets. The inheritance pattern is related to the X chromosome. Most constant feature is hypophosphatemia. Pathogenesis is still a subject of controversy. There are three main theories: a) An abnormal vitamin D metabolism. b) Secondary hyperparathyroidism developping as a result of the diminished calcium absorption by gut. c) A primary deffect of phosphate transport al various levels. Authors study and comment six cases of X.L.F.H.R., three of which belong to the same family. Clinical, radiological and higtological findings correspond to those of severe rickets. It is a chronic disease which affects children during growth period, giving rise to deforming bones invalidism. Treatment consists on continuous administration of oral phosphate and vitamin D.