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Researchers at the National Institutes of Health and other institutions have discovered the third in a sequence of genes that accounts for previously unexplained forms of osteogenesis imperfecta (OI), a genetic condition that weakens bones, results in frequent fractures and is sometimes fatal.

The newly identified gene contains the information needed to make the protein Cyclophilin B. This protein is part of a complex of three proteins that modifies collagen, folding it into a precise molecular configuration, before it is secreted from cells. Collagen functions as molecular scaffolding that holds together bone, tendons, skin and other tissues.

Most types of osteogenesis imperfecta result from a dominant mutation in collagen itself, requiring only one copy of the mutated gene to bring about the disorder. Osteogenesis imperfecta involving the Cyclophilin B gene is a recessive trait, requiring two defective copies of the gene to cause the disorder.

“The discovery provides insight into a previously undescribed form of osteogenesis imperfecta,” said Alan E. Guttmacher, M.D., acting director of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). “The advance also provides new information on how collagen folds during normal bone formation, which may also lead to greater understanding of other bone disorders.”

The finding was published online Jan. 20 in the New England Journal of Medicine. The investigation involved a collaboration between researchers at the NICHD, led by Dr. Joan Marini, and the Hospital for Special Surgery in New York City. There, Dr. Cathleen Raggio diagnosed the children in the study as having a novel form of OI. In addition, researchers at the University of Washington in Seattle and the NIH’s National Human Genome Research Institute also took part in the study.

The NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases estimates that in the United States a minimum of 20,000 and possibly as many as 50,000 people are affected by osteogenesis imperfecta (http://www.niams.nih.gov/Health_Info/Bone/Osteogenesis_Imperfecta/default.asp). About 85 percent of all OI cases are caused by mutations in the genes that contain the information needed to make collagen.

Researchers at the NICHD and other institutions had earlier learned that osteogenesis imperfecta could also be caused by defects in the protein complex that modifies collagen into its final form. Joan Marini, M.D., Ph.D., chief of NICHD’s Bone and Extracellular Matrix Branch and colleagues had discovered that recessive mutations in the genes for two proteins in the complex, cartilage associated protein, or CRTAP (http://www.nichd.nih.gov/news/releases/brittle_bone_disease.cfm) , and prolyl 3-hydroxylase 1 ( P3H1) (http://www.nichd.nih.gov/news/releases/gene_recessive_bone_disease.cfm), could result in severe forms of osteogenesis imperfecta. Individuals with mutations in CRTAP have all died in childhood. Mutations in P3H1 are sometimes fatal in early life.

A new gene involved in a recessive form of brittle bone disease has been pinpointed by researchers.

The gene is the third to be identified in a sequence of genes involved in previously unexplained forms of osteogenesis imperfecta, a sometimes fatal genetic condition that weakens bones, resulting in frequent fractures.

The new gene, discovered by U.S. National Institutes of Health researchers and their colleagues, is involved in the production of Cyclophilin B, which is part of a complex of three proteins that folds collagen into a precise molecular configuration before it’s secreted from cells.

Collagen acts as the molecular scaffolding that holds together bone, tendons, skin and other tissues.

Most types of osteogenesis imperfecta are the result of a dominant mutation in collagen itself, requiring only one copy of the mutated gene to cause the condition, the researchers explained in an NIH news release. Osteogenesis imperfecta involving the Cyclophilin B gene is a recessive trait, requiring two defective copies of the gene to cause the disorder.

Identification of this new gene “provides insight into a previously undescribed form of osteogenesis imperfecta. The advance also provides new information on how collagen folds during normal bone formation, which may also lead to greater understanding of other bone disorders,” Dr. Alan E. Guttmacher, acting director of the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in the news release.

The study is published in the Jan. 20 issue of the New England Journal of Medicine.

Plasma jets could offer a painless alternative to dentists’ drills, say German researchers.

They found that firing low temperature plasma beams at dentin — the fibrous tooth structure beneath the enamel coating — reduced the amount of dental bacteria by up to 10,000-fold. The results suggest that plasma jets could be used to remove infected tissue in tooth cavities, a procedure that currently requires a drill.

For the study, the researchers infected dentin from extracted human molars with four strains of bacteria and then exposed the dentin to plasma jets for 6, 12 or 18 seconds. The amount of bacteria that was eliminated increased the longer the dentin was exposed to the plasma jets.

The study is in the February issue of the Journal of Medical Microbiology.

“Drilling is a very uncomfortable and sometimes painful experience,” the study’s leader, Dr. Stefan Rupf, of Saarland University in Homburg, said in a news release from the journal’s publisher. “Cold plasma, in contrast, is a completely contact-free method that is highly effective.”

Rupf said that “huge progress” is being made in the field of plasma medicine and that “a clinical treatment for dental cavities can be expected within three to five years.”

SOURCE: Society for General Microbiology