This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Progressive osseous heteroplasia (POH) is a progressive bone disorder in which bone forms (ossifies) within skin and muscle tissue. It usually becomes apparent in infancy with skin (cutaneous) ossification, which progresses to involvement of subcutaneous and deep tissues, including muscle. In some cases, it first becomes apparent later in childhood or in early adulthood. Ossification may cause pain and open sores (ulcers) in affected areas of the body. Joints may become involved over time, causing impaired mobility. POH is caused by a mutation in the GNAS gene and is inherited in an autosomal dominant manner. In most cases, the mutation occurs randomly in a person with no family history of POH. In some cases, the mutation is inherited from a parent. There are currently no effective treatments for POH, and surgery to remove widespread lesions often results in recurrences or complications. However, well-circumscribed lesions can often be removed with successful, long-term results.
POH is thought to be part of a spectrum of related genetic disorders which include Albright hereditary osteodystrophy, pseudohypoparathyroidism, and primary osteoma cutis. These disorders share the features of superficial ossification and being caused by mutations affecting the GNAS gene.
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