Scientists at U.S. biotechnology company Regeneron Pharmaceuticals have studied a rare genetic disease that creates a second skeleton and were able to discover a treatment that can shut down the excessive bone growth. The preliminary tests of the treatment were conducted on mice engineered to develop the illness.

Company scientists announced on Sept 3, that the protein Activin-A with a role to normally block bone growth may trigger hyperactive bone growth in patients with a certain genetic mutation.  The rare genetic disease is known as Fibrodysplasia Ossificans Progressiva (FOP).

The researchers found out an antibody that blocks Activin-A can help to shut down the growth signal in mice genetically modified to develop the disease. According to the study, the effect lasted as long as six weeks. The research papers were published in the journal Science Translational Medicine.

Aris Economides, co-founder of the Regeneron Genetics Center and executive director of skeletal diseases, declared that the findings could eventually help designing a treatment for the disease. FOP is a lethal genetic disorder in an extra skeleton is created when soft tissue and muscle are gradually replaced by bone. The extra skeleton immobilizes patients and eventually suffocates them.

According to statistics, this rare medical condition affects currently 200 people in the U.S. and a total of 800 people globally. According to scientists, FOP is caused by mutations in the gene ACVR1 that has the role in producing a receptor that controls bone growth in cells. The genetics company Regeneron discovered that this mutated receptor presents an abnormal response into Activin-A, a growth factor secreted by the immune system in response to inflammation and injury.

Normally, Activin-A blocks the receptor, but in individuals with the FOP mutation, Activin-A has the opposite effect, as Economides explained for Reuters. The finding of the new research explains how abnormal bone forms in FOP patients, he added.

Researchers were able to develop a therapeutic antibody designed to block Activin-A. The drug blocked the formation of an excess bone when it was injected in mice that developed a form of the disease. According to Economides, the antibody works in a similar way to Sanofi and Regeneron's newly approved antibody drug Praluent. Regeneron's findings help explain some of science behind FOP and also raise hope for a new treatment approach.