[Early infantile malignant osteopetrosis. Experiences with drug therapy].

The autosomal recessive form of osteopetrosis becomes manifest in early infancy and often is lethal during the first decade of life. In an infant diagnosed at the age of eight weeks, a therapy with Calcitriol (Rocaltrol) was initiated with the intention to stimulate the osteoclast activity and to improve the bone marrow insufficiency. During therapy, a massive diarrhoea has been observed as potential and previously undescribed side effect of Calcitriol. Therefore the therapy had to be discontinued. A simultaneous trial with Ca-depleted diet did not show any effect. In the absence of a suitable donor, a bone-marrow transplantation could not be performed. The patient died at the age of five month.