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Osteopetrosis, 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.
The impairment of bone metabolism causes inadequate bone mineralization. Osteomalacia in children is known as rickets, and because of this, use of the term "osteomalacia" is often restricted to the milder, adult form of the disease. Signs and symptoms can include diffuse body pains, muscle weakness, and fragility of the bones.
Bone is broken down by osteoclasts, and rebuilt by osteoblasts, both of which communicate through cytokine (TGF-β, IGF) signalling. Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. [1]
In bone, mineralization starts from a heterogeneous solution having calcium and phosphate ions. The mineral nucleates, inside the hole area of the collagen fibrils, as thin layers of calcium phosphate, which then grow to occupy the maximum space available there. The mechanisms of mineral deposition within the organic portion of the bone are ...
Bone tissue is a dynamic system with active metabolism. [24] Bone tissue remodelling or bone remodeling is a successive chain of old bone matrix removal and its replacement with a new one. [25] These processes make a child’s skeleton grow and extend, while childhood is characterized by bone tissue growth rather than its resorption.
One of the principal causes of arterial stiffening with age is vascular calcification. Vascular calcification is the deposition of mineral in the form of calcium phosphate salts in the smooth muscle-rich medial layer of large arteries including the aorta. DNA damage, especially oxidative DNA damage, causes accelerated vascular calcification. [11]
Osteoporosis is diagnosed when the bone mineral density is less than or equal to 2.5 standard deviations below that of a young (30–40-year-old [4]:58), healthy adult women reference population. This is translated as a T-score. But because bone density decreases with age, more people become osteoporotic with increasing age.
On the other hand, CKD-MBD is defined as a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: 1) abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism; 2) abnormalities in bone turnover, mineralization, volume, linear growth, or strength (renal osteodystrophy ...