[Idiopathic juvenile osteoporosis (author's transl)].

A young girl aged 13 years was hospitalized for metaphyseal fractures of both knees, and was found to have idiopathic juvenile osteoporosis which followed a favourable course over a period of one year. The authors recall the difficulties encountered in diagnosing this rare affection as no specific biological changes have been demonstrated. The criteria used are: the age of the patient, the disease usually becoming evident in the prepuberty period, the contrast between the very severe osteoporosis noted on radiological examination and the perfect general condtion of the patient, the negative biological tests results, and finally, the spontaneous repair of the osteoporosis in one to four years.