<unk> , literally "stone bone", also known as marble bone disease or Albers-Schönberg disease, is an extremely rare inherited disorder whereby the bones harden, becoming denser, in contrast to more prevalent conditions like osteoporosis, in which the bones become less dense and more brittle, or osteomalacia, in which the bones soften.<unk>  can cause bones to dissolve and break. It is one of the hereditary causes of osteosclerosis. It is considered to be the prototype of osteosclerosing dysplasias. The cause of the disease is understood to be malfunctioning osteoclasts and their inability to resorb bone. Although human<unk>  is a heterogeneous disorder encompassing different molecular lesions and a range of clinical features, all forms share a single pathogenic nexus in the osteoclast. The exact molecular defects or location of the mutations taking place are unknown.<unk>  was first described in 1903, by German radiologist Albers-Schönberg.
Osteopetrosis
Avascular necrosis
Leri pleonosteosis
Osteochondrosis
Osteitis fibrosa cystica
Osteofibrous dysplasia
Osteoma
Osteopoikilosis