DNA sequencing electropherograms of a typical<unk>  patient being compared to other 2 patients. The unsure base "N" indicates site heterozygous for mutation and wild-type gene.<unk>  is an autosomal dominant disorder. Thus, a child of an affected heterozygous parent and an unaffected parent has a 50% probability of being affected. Two affected individuals can produce unaffected children. Two unaffected individuals can produce an affected offspring as a result of the mutation of the gene. The homozygous dominant form is more severe than the heterozygous form. The protein that causes ossification is normally deactivated by an inhibitory protein after a fetus's bones are formed in the womb, but in patients with<unk> , the protein keeps working. Aberrant bone formation in patients with<unk>  occurs when injured connective tissue or muscle cells at the sites of injury or growth incorrectly express an enzyme for bone repair during apoptosis (self-regulated cell death), resulting in lymphocytes containing excess bone morphogenetic protein 4 (BMP4) provided during the immune system response. The bone that results occurs independently of the normal skeleton, forming its own discrete skeletal elements. These elements, however, can fuse with normal skeletal bone. The diaphragm, tongue, and extra-ocular muscles are spared in this process, as well as cardiac and smooth muscle. Since the incorrect enzyme remains unresolved within the immune response, the body continues providing the incorrect BMP4-containing lymphocytes. BMP4 is a product that contributes to the development of the skeleton in the normal embryo. The ACVR1 gene encodes a bone morphogenic protein (BMP) receptor; this gene is mutated in<unk> . It is responsible for growth and development of bone and muscles. The typical mutation, R202H, makes the inhibitor FKBP1A bind less tightly to the activation GS-loop. The end result is that ACVR1 is not effectively turned off, and an overgrowth of bone and cartilage and fusion of joints occurs. Atypical mutations involving other residues work similarly. In some cases, the receptor can end up signalling that it's active without being bound to its activating ligand. Most of the cases of<unk>  were results of a new gene mutation: these people had no history of this particular disorder in their family. There are some cases where the individual has inherited the mutation from one affected parent.
Fibrodysplasia ossificans progressiva
Fibrous dysplasia of bone
Myositis ossificans
Langer–Giedion syndrome
Gerodermia osteodysplastica
Osteitis fibrosa cystica
Enchondromatosis
Osteoma cutis