The various types of<unk>  are caused by genetic changes (mutations) in one of at least ten genes. There is nothing a parent can do before, during or after a pregnancy to cause<unk>  in a child. The genes associated with<unk>  are involved in the development and/or function of osteoclasts, cells that break down bone tissue when old bone is being replaced by new bone (bone remodeling). This process is necessary to keep bones strong and healthy. Mutations in these genes can lead to abnormal osteoclasts, or having too few osteoclasts. If this happens, old bone cannot be broken down as new bone is formed, so bones become too dense and prone to breaking. * Mutations in the CLCN7 gene cause most cases of autosomal dominant<unk> , 10-15% of cases of autosomal recessive<unk>  (the most severe form), and all known cases of intermediate autosomal<unk> . * Mutations in the TCIRG1 gene cause about 50% of cases of autosomal recessive<unk> . * Mutations in the IKBKG gene cause X-linked<unk> . * Mutations in other genes are less common causes of<unk> . * In about 30% percent of affected people, the cause is unknown. Normally, bone growth is a balance between osteoblasts (cells that create bone tissue) and osteoclasts (cells that destroy bone tissue). Sufferers of<unk>  have a deficiency of osteoclasts, meaning too little bone is being resorbed, resulting in too much bone being created. Gene variation Name OMIM Gene<unk> TA1 LRP5 receptor<unk> TA2 CLCN7 chloride channel<unk> TB1 TCIRG1 ATPase<unk> TB2 RANKL<unk> TB3 CA2 (renal tubular acidosis)<unk> TB4 CLCN7 chloride channel<unk> TB5 OSTM1 ubiquitin ligase<unk> TB6 PLEKHM1 adapter protein<unk> TB7 TNFRSF11A (RANK receptor)
Osteopetrosis
Avascular necrosis
Leri pleonosteosis
Osteochondrosis
Osteitis fibrosa cystica
Osteofibrous dysplasia
Osteoma
Osteopoikilosis