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?
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 GNASgene and is inherited in an autosomal dominant pattern.
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.
The GNASgene 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.
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.
Last updated: 10/17/2012
How can I find a genetics professional in my area?