PTPN11 and skeletal dysplasia: In addition to testing for mutations in ACVR1, clinicians can also implicate other genes whose aberrant activity causes clinical pictures that overlap with FOP using more comprehensive genomic exome sequencing or a skeletal dysplasia panel, which tests for mutations in ~20 genes, including EXT1/2, GNAS, PTPN11, and ROR2 [8].