Patients with serious diseases often find comfort in support groups. That option isn't practical for Erin Danzer, 11, who has a progressively immobilizing bone disease called fibrodysplasia ossificans progressiva, or FOP. She's the only one in San Diego County so afflicted, said her mother, Lori Danzer.

But the Oceanside girl is going to meet a lot of her FOP peers Aug 7-9, when 22 teens and young adults with the disease arrive in San Diego for a meeting, giving them a chance to bond with others in their situation.

Fibrodysplasia ossificans progressiva causes excessive bone growth, fusing joints, muscles and connective tissue so people gradually lose the ability to move. They end up trapped inside a chamber of their own bone.

Community fund-raisers are also being held the weekend of Aug. 9-10 (see box).

Getting the word out for the fundraisers, the first for the disease in San Diego County, has been difficult, Lori Danzer said.

"Because it's so unknown, people don't pay attention," she said.

Why bother with such a rare disease, with just 700 diagnosed cases in the world? Because it can provide information for treating more common bone diseases, Lori Danzer said.

"The bone that grows is healthy bone," she said. Learning how to turn off bone production will inevitably shed light on how to turn on bone production.

"So many other illnesses -- arthritis, osteoporosis, spinal cord injuries and other bone-related diseases -- would benefit from a cure for FOP," she said.

Staying active

Fibrodysplasia ossificans progressiva is an unpredictable disease. It strikes roughly 1 of every 2 million people, without any discernable pattern by race or ethnicity. While the general outlook for patients is immobilization over a period of decades, individual patients progress at different rates. Many enjoy long periods in which the disease apparently lies dormant, only to flare up later.

For now, Lori Danzer is taking care of her daughter much the same way as she has been since the North County Times profiled her in spring 2007. Danzer's goal is to give Erin as much of a normal life as possible. She attends school, and is now in sixth grade.

"She's got some more bone in her back and lost some mobility. She can't move her neck easily," Danzer said.

In fact, Erin doesn't seem to like admitting there's anything she can't do, judging from a phone conversation with her Monday from Jackson Hole, Wyo., just after returning from a chipmunk-searching expedition. Before that, she had been hiking with her father, Kenneth. Her favorite sport is swimming.

When asked whether FOP makes swimming difficult for her, Erin said it doesn't. And when asked whether she was looking forward to the upcoming meeting, she kept her preteen cool:

"Sort of," she said.

What does she talk about with others who have FOP?

"Regular stuff."

Genetic detonation

Dark-haired with a shy smile, Erin looks on the surface like any other healthy, happy girl. But inside, she's becoming locked in a prison of her body's own making.

FOP causes muscles and connective tissues like tendons and ligaments to turn into bone. As the disease progresses, the patient becomes wrapped in sheets of bone. There is no cure -- removing the bone causes it to regrow even faster, doctors say. Symptoms are eased by some treatments, such as corticosteroids and immunosuppressive medication used with organ transplants to prevent rejection.

It's a genetic disease, caused by a one-letter-misspelling of the genetic alphabet in a single gene. This errant gene causes production of a malformed protein that causes the abnormal bone production, said Dr. Frederick S. Kaplan, one of the world's foremost experts on FOP.

However, the gene alone isn't responsible for causing the body to make bone, said Kaplan, director of the Center for FOP and Related Disorders at the University of Pennsylvania School of Medicine. Some unknown trigger causes the disease to flare up unpredictably, Kaplan wrote in a report.

"For many years, we said that an FOP flare-up was like an atom bomb, a bad switch due to a faulty gene," the report stated. "The episodic nature of FOP always suggested that the mutation alone would be insufficient. The FOP gene sets the stage. It is the fuse, but it is not enough. It must be triggered and detonated, and when it is, it sets in motion a chain reaction that obliterates all semblance of normality."

Triggers for flare-ups include viruses, muscle fatigue, injuries, even immunization shots into muscle, Kaplan said in an interview.

"We're studying the wiring diagram of this bomb, so that we can inactivate the fuse," he said.

The good news is that basic research has discovered a lot about how the disease works, Kaplan said. That has enabled scientists to create a model of the disease in mice, the so-called "FOPPY mouse."

Researchers now have enough knowledge to make educated guesses about what kinds of drugs might work, and they are now testing various potential therapies on the mouse model, Kaplan said. That gives cause for hope that a safe and effective treatment can be found for the mouse, which could then be tested in humans.

But getting a potential drug into humans is still a long way off, Kaplan said. Until then, the research --- and the waiting by patients, their friends and families -- will continue.

Call staff writer Bradley J. Fikes at 760-739-6641. Read his blogs at bizblogs.nctimes.com.

BREAKOUT BOX

Several days of activities for research into fibrodysplasia ossificans progressiva will be held from Aug. 7-9:

- Aug. 7-9, IFOPA teen and young adult meeting, San Diego Marriott Gaslamp Quarter, 660 K St., San Diego. The focus for this meeting is to balance information, workshops, clinics, and social time in a way that is appealing to teens and young adults. Call 407-365-4194; e-mail: together@ifopa.org.

- Aug. 9-10, Erin's Day at Morgan Run Club & Resort, and Capriccio Salon and Day Spa: On Aug. 9, events will take place at Capriccio Salon & Day Spa, 3150 El Camino Real Suite A, Carlsbad, such as haircuts and massages for $25, or a haircut-a-thon and dinner ticket for $100. Call 760-730-3022.

On Aug. 10, duffers get into the act with an "Erin's Day" golf tournament at Morgan Run Club & Resort in Rancho Santa Fe. A golf and dinner package for one is $250 and for a foursome, $1,000.

For information on the young adult meeting, go to www.ifopa.org, and look under "Events" for IFOPA Teen/Young Adult Meeting. Information on the fundraiser is listed directly below that notice.

Those wishing to help with the fundraiser can also call 760-803-4934.