[Bartter's syndrome, chondrocalcinosis and hypomagnesemia].

In two cases of Bartter's syndrome with hypomagnesaemia the authors report radiological findings typical of chondrocalcinosis associated with joint symptoms corresponding to this condition. In Bartter's syndrome there is, in addition to hypokalaemic alkalosis, often concomitant magnesium depletion which has marked repercussions with respect to both physiopathology and symptomatology. In particular, hypomagnesaemia could well be important in the pathogenesis of chondrocalcinosis through two simultaneous mechanisms: by reducing the activity of pyrophosphatases and by facilitating the crystallisation of pyrophosphates. These mechanisms could explain the association of Bartter's syndrome and chondrocalcinosis, which is described here for the first time.