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Bone ossification, or osteogenesis, is the process of bone formation. This process begins between the sixth and seventh weeks of embryonic development and continues until about age twenty-five, although this varies slightly based on the individual. There are two types of bone ossification: intramembranous and endochondral. Each of these processes begins with a mesenchymal tissue precursor, but how it transforms into bone differs. Intramembranous ossification directly converts the mesenchymal tissue to bone and forms the flat bones of the skull, clavicle, and most of the cranial bones. Endochondral ossification begins with mesenchymal tissue transforming into a cartilage intermediate, which is later replaced by bone and forms the remainder of the axial skeleton and the long bones.

Cleidocranial Dysplasia (CCD) [9] CCD occurs due to a mutation in CBFA1/RUNX2 (runt-related transcription factor 2) gene, which directs osteoblast differentiation - CCD is an autosomal dominant condition resulting in short stature, patent fontanelles, and supernumerary teeth Camptomelic Dysplasia (CMD) [10] [11] CMD occurs due to a mutation in SOX9 (SRY-box 9) gene, which directs chondrocyte differentiation - CMD is an autosomal dominant condition that results in the bowing of long bones, and this condition usually results in neonatal death due to respiratory failure Osteogenesis Imperfecta (OI) [12] OI occurs due to a mutation in COL1A1 (collagen type I alpha 1 chain) or COL1A2 (collagen type I alpha 2 chain) genes, which encode the major component of type 1 collagen; this is an autosomal dominant condition that results in very fragile bones Achondroplasia [13] Achondroplasia occurs due to a mutation in FGFR3 (fibroblast growth factor receptor 3) gene, which aids in the formation of collagen and plays a role in the ossification of bone - this mutation prevents adequate bone formation in utero and results in a shortened stature Acromegaly  [14] Acromegaly occurs due to an increased amount of growth hormone and insulin-like growth factor-1. Causes of acromegaly include pituitary tumors and McCune-Albright syndrome. These factors have anabolic effects on cartilage and bone metabolism. The increased factors both cause the increased growth of bone and degenerative changes to cartilage resulting in arthropathy. Rickets [15] Rickets is most commonly caused by a vitamin D deficiency, which leads to the softening and weakening of bones in children. The main mechanism is insufficient calcification at the growth plate during bone formation. Symptoms of Rickets disease include bowed legs, spinal curvatures, rachitic rosary, and craniotabes.  Rickets results in failure of apoptosis of the hypertrophic chondrocyte in the physeal plate. Eventually, this leads to a cupping appearance of the epiphyseal ends of the bones.