Progressive Heterotopic Heteroplasia

**Semantic type:** Finding

**Definition:** Loss of function mutation(s) in the paternal allele of the GNAS gene, encoding guanine nucleotide-binding protein G(s) subunit alpha isoforms short resulting in dermal ossification beginning in infancy, followed by increasing and extensive heterotopic bone formation in deep muscle and fascia.

**Synonyms:** - Osteoma Cutis - Progressive Osseous Heteroplasia