ACVR1 and fibrodysplasia ossificans progressiva: A sanger sequencing analysis targeting a known hot-spot mutation was sent on peripheral blood from both probands A and B. ACVR1 exon 6 c.617 G>A p. Arg206His (NM_001105.4) heterozygous pathogenic variant was found, and this confirmed the diagnosis of FOP in both brothers.