Osteopetrose

This is a rare genetic disease characterized by decreased osteoclast (bone) resorption process. Its result is symmetric osteosclerosis. Bones become very fragile and break like chalk. This disease is also called marble bone disease or Albers-Schönberg disease. There are 4 types of osteopetrosis identified: a malignant type in children caused by carbonic anhydrase II deficiency, and two autosomal dominant types (frequency of all forms – about 1:20 000). The best studied is the type of osteopetrosis caused by carbonic anhydrase deficiency. This enzyme catalyzes the secretion of hydrogen ions (acidifying the environment) in osteoclasts and kidney tubule cells. When carbonic anhydrase activity decreases, the formation of resorption lacunae (cavities) in osteoclasts is disturbed, as well as the dissolution of hydroxyapatite crystals, and acidification of urine in kidney cells. In the case of the malignant childhood type, symptoms worsen immediately after birth, characterized by bone fragility, anemia (due to decreased bone marrow), hydrocephalus, and early death. Autosomal dominant forms are more common in adults. They often experience bone fractures, as well as anemia. Bone marrow transplantation can be a treatment option that restores normal osteoclast activity.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė