Clinical feature: 

Definition: Progressive osseous heteroplasia is caused by inactivating mutations of the GNAS gene and characterized by intramembranous bone tissue. The skeleton invariably shows deformations too.

Literature: 

Adegbite NS et al. (2008) Diagnostic and mutational spectrum of progressive osseous heteroplasia (POH) and other forms of GNAS-based heterotopic ossification.
Athanasou NA et al. () Progressive osseous heteroplasia: a case report.
Bastepe M et al. (2005) GNAS locus and pseudohypoparathyroidism.
Brook CG et al. (1971) Osteoma cutis and Albright's hereditary osteodystrophy.
Eddy MC et al. (2000) Deficiency of the alpha-subunit of the stimulatory G protein and severe extraskeletal ossification.
Faust RA et al. (2003) Progressive osseous heteroplasia in the face of a child.
Fawcett HA et al. (1983) Hereditary osteoma cutis.
Gardner RJ et al. (1988) Familial ectopic ossification.
Izraeli S et al. (1992) Albright hereditary osteodystrophy with hypothyroidism, normocalcemia, and normal Gs protein activity: a family presenting with congenital osteoma cutis.
Kaplan FS et al. (1994) Progressive osseous heteroplasia: a distinct developmental disorder of heterotopic ossification. Two new case reports and follow-up of three previously reported cases.
MacLean GD et al. (1966) Connective tissue ossification presenting in the skin.
Rosenfeld SR et al. (1995) Progressive osseous heteroplasia in male patients. Two new case reports.
Schmidt AH et al. (1994) Hemimelic progressive osseous heteroplasia. A case report.
Shore EM et al. (2002) Paternally inherited inactivating mutations of the GNAS1 gene in progressive osseous heteroplasia.
Stoll C et al. () Progressive osseous heteroplasia: an uncommon cause of ossification of soft tissues.
Urtizberea JA et al. (1998) Progressive osseous heteroplasia. Report of a family.