Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.


Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Progressive osseous heteroplasia

Other Names for this Disease
  • Ectopic ossification familial type
  • Familial ectopic ossification
  • Osteoma cutis
  • POH
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

My 17-year-old daughter has progressive osseous heteroplasia and the time has come for me to discuss with her the consequences of this disease in regard to having children of her own. Can you please send be any information you have?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is progressive osseous heteroplasia?

Progressive osseous heteroplasia is an inherited condition in which bone forms within skin and muscle tissue. Bone that forms outside the skeleton is called heterotopic or ectopic bone. In this condition, ectopic bone formation begins in the deep layers of the skin (dermis and subcutaneous fat) and gradually moves into other tissues such as skeletal muscle and tendons. The bony lesions within the skin may be painful and may develop into open sores (ulcers). Over time, joints can become involved, resulting in impaired mobility. This condition is caused by mutations in the GNAS gene and is inherited in an autosomal dominant pattern.[1]
Last updated: 1/10/2013

How is progressive osseous heteroplasia inherited?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. People normally inherit one copy of each gene from their mother and one copy from their father. For most genes, both copies are active, or "turned on," in all cells. For a small subset of genes, however, only one of the two copies is active. For some of these genes, only the copy inherited from a person's father (the paternal copy) is active, while for other genes, only the copy inherited from a person's mother (the maternal copy) is active. These differences in gene activation based on the gene's parent of origin are caused by a phenomenon called genomic imprinting.[1]

The GNAS gene has a complex genomic imprinting pattern. In some cells of the body the maternal copy of the gene is active, while in others the paternal copy is active. Progressive osseous heteroplasia occurs when mutations affect the paternal copy of the gene. Thus, progressive heteroplasia is usually inherited from the father.[1]
Last updated: 1/10/2013

What is the chance that a woman with progressive osseous heteroplasia will have children with this condition?

In those with progressive osseous heteroplasia, the defective copy of the GNAS gene is inherited from the father. If a defective GNAS is inherited from the mother, individuals typically develop the related, yet distinct, disorder known as pseudohypoparathyrodism type 1a (PHP1a), which is usually seen in association with Albright's hereditary osteodystrophy (AHO). Thus, women with progressive osseous heteroplasia have a 50% chance of having children with PHP1a and AHO. To read more about these conditions, click on the links above.[1]
Last updated: 10/17/2012

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 10/18/2013