A plea for a rare disease: Illness turns muscles into bone

By: BRADLEY J. FIKES - Staff Writer | Monday, April 30, 2007 2:10 PM PDT ∞

OCEANSIDE ---- Health care is best at treating people with common afflictions, which is good news for people with diabetes, heart disease or breast cancer. But those with rare or so-called "orphan" diseases often have trouble getting attention from the medical establishment.

Erin Danzer, 8, has such an orphan disease. It progressively turns muscle and connective tissue into bone. Those so afflicted gradually lose their ability to move. They often wind up locked into one position, a living mummy. Patients usually die in their mid-40s. It has a jawbreaker of a name, typical of diseases not common enough to get vernacular monikers: fibrodysplasia ossificans progressiva, or FOP.

Injuries hasten the disease, so Lori Danzer, Erin's mother, is trying to protect her while allowing her as normal a life as possible.

"She's a kid ... and I try not to stop her from doing the things she wants to do, because she does deserve to have a life," Danzer said.

About 600 people worldwide are known to have the illness, according to the International Fibrodysplasia Ossificans Progressiva Association. The total number of those with the disease is estimated to be about 2,000. The association is on the Web at www.ifopa.org.

Lori Danzer is stressing a practical reason for research into FOP: If the reason for the abnormal bone growth is discovered, it could guide the search for remedies for more common bone diseases, such as osteoporosis.

And there's been progress: A year ago, researchers at the University of Pennsylvania School of Medicine found the so-called "skeleton key," a gene that, when mutated, triggers the bone formation process.

One of the researchers, Dr. Frederick Kaplan, has been studying the disease for 15 years. Kaplan said he deliberately chose a rare disease in the belief that understanding its cause would shed light on the normal process of bone development.

"It's a catastrophic sabotage of the body's skeletal system," Kaplan said of the incurable disease.

Kaplan, who saw Erin at a recent fundraiser in Santa Maria, said he really became emotionally involved after seeing children with the disease, and watching the transformation take place in them. Examining adults who have the full-blown disease is like visiting the site of the Sept. 11 attacks, Kaplan said ---- it's hard to imagine them as they used to be. When the disease is in children, he said, it's like watching a video of the World Trade Center collapsing ---- you can see how their life is being taken away from them.

Over time, "bridges" of bone form across joints, as muscles, tendons and ligaments become ossified, or turned into bone. This "second skeleton," as it's called, locks the joints into place. Ribbons of bone enclose the chest, restricting breathing, and forcing the heart to work harder. Removing the bone only makes things worse, because removal provokes a more extensive regrowth.

Dramatic evidence comes from the skeleton of Harry Eastlack, a man with FOP who died just before turning 40. He donated his body to science, and his skeleton is on display at the Mutter Museum of the College of Physicians in Philadelphia. The IFOPA's Web site describes it vividly:

"Sheets of bone cover Harry Eastlack's back. Ribbons, sheets, and plates of bone lock his spine to his skull and his skull to his jaw. Additional ribbons and cordons of bone span from the spine to the limbs and immobilize the shoulders, elbows, hips, and knees. Thin stalagmites of bone launch themselves from his pelvis and thighs. His upper arms are welded to his breastbone by slender white bridges of bone that cross his immobilized rib cage."

Kaplan said the disease varies in intensity, and its course is impossible to predict. He's seen people with it die as young as age 8 or live into their 80s.

Discovery of the "skeleton key" gene is a huge boost, Kaplan said, and it's expected to lead to a drug that can turn off the gene's abnormal activity. In addition, ways may be found to switch on the bone-producing gene where it's needed in those who don't produce enough bone. Those with slow-healing fractures or spinal fusions could benefit, he said.

But Kaplan said he won't give a timeline for developing a drug with that genetic knowledge, because the research is still in its earliest phases. He hazards a guess that a potential drug could be selected for clinical testing in about 10 years.

Because the disease is so rare, diagnosis is difficult. Looking back, Danzer said, the signs of the disease were present at birth: characteristically malformed big toes. Erin developed bumps on her head that would turn hard.

"We had a biopsy done on her head, and they never gave us an answer really of what it was," Danzer said.

When Erin was 11 months old, she was diagnosed with the disease.

Today, Erin has lost some mobility, but still keeps active. She can't easily raise her arms above her head, or bend over to tie her shoes. That hasn't stopped her, Danzer said.

"She's really got a good attitude," Danzer said. "If she can't do something one way, she'll figure out another way to do it."

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.

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