Autosomal malignant osteopetrosis. From diagnosis to therapy.

Osteopetrosis is a heterogeneous family of rare human genetic disorders due to markedly decreased bone resorption. It is one among disorders causing osteosclerosis of the trabecular bone and/or hyperostosis of the cortical bone. Four types of human osteopetrosis have been clearly defined, but patients with atypical symptoms are frequent, suggesting that there are additional forms. The most severe expression of this condition in its malignant form is inherited as an autosomal recessive disorder and it is usually fatal before school age. It presents with failure to thrive, severe hepatosplenomegaly, pancytopenia and nerve compression leading to blindness and deafness during infancy. The case of a 2-month-old female child with severe hepatosplenomegaly, failure to thrive, nystagmus, pancytopenia, gengival hyperplasia, optic atrophy, absent evoked visual potential and increased bone density within the total skeleton, is reported. Diagnosis of autosomal recessive malignant osteopetrosis was established by transiliac bone biopsy. She underwent bone marrow transplantation, but died soon afterwards. This rare and mortal disorder of bone formation requires early diagnosis and immediate pharmacological treatment, consisting in administration of vitamin D, in order to enhance bone resorption and of prednisone to improve hematological indexes and, if possible, bone marrow transplantation in order to ameliorate quality of life and survival.