PITTSBURGH, AUG. 10 -- Eleanor Jordan was frightened when her 2 1/2-year-old daughter fell out of bed and broke her nose and jaw, but her fear was more than a mother's concern for an injured child.

"I didn't even want to take her to the doctor," she said. "I was absolutely terrified, because I knew what would happen."

She feared she would be charged with child abuse for the second time. The broken nose and jaw Narelle suffered two summers ago were her sixth and seventh fractures.

Neither Jordan nor her doctor knew then that her daughter suffered from osteogenesis imperfecta, a rare ailment also known as brittle-bone disease.

The disease leads to frequent fractures but often is difficult to detect, and the inability of many parents, doctors and social workers to recognize its symptoms has led to charges of child abuse in a number of cases, experts say.

The disease affects about 40,000 people across the country, said Heidi Glauser, president of the Osteogenesis Imperfecta Foundation.

About 500 members of the group are meeting this weekend in Pittsburgh. Among the topics on the agenda are athletic conditioning for brittle-bone patients, their rights and research on the genetic cause of the disease, whch leads to a lack of the protein collagen in bones.

About once every two months, parents report to the organization that they have been accused of child abuse, said Glauser, of Pittsburgh, whose 7-year-old son has the illness.

Narelle's fractures resulted from spills and tumbles common to toddlers.

Her parents, of Norwood, Mass., did not learn about osteogenesis imperfecta until after more than a year of trips to hospitals, visits from police and investigations by social workers. A doctor suspected the disease and sent Narelle to a geneticist, who confirmed it in early 1989 through a tissue test.

Jordan said she remains bitter about the treatment her family received. "I still go crazy because the medical profession could be so ignorant and put us through the hell they did," she said Thursday. "Here I was thinking everybody was on our side -- going to help us -- and nobody was going to do anything except accuse us of child abuse."

Authorities placed Narelle under the care of Jordan's mother for several days in 1987 after doctors who treated her for two leg fractures reported the injuries to social workers, saying they suspected child abuse. A judge allowed the girl to return to her parents after a hearing.

When Narelle was treated for the broken nose and jaw, the family's lawyer urged Jordan to take Narelle home rather than leave her in the hospital.

Shortly after they got home, three police cars and two social workers arrived, seeking to take Norelle into protective custody, but were stopped by the family lawyer.

Anna and Steven Moxham of Stamford, N.Y., lost custody of their daughter, Dawn, for six months this year because of abuse allegations. The girl, 2, was returned to the couple in June, after the diagnosis was confirmed through a tissue test, her mother said.

Now, Anna Moxham's biggest worry is what will happen if her daughter breaks another bone.

"Am I going to go back to court because she sustained a fracture? Because she fell? I can't live like that," she said. "I live my life on pins and needles."

An official at the National Association of Social Workers said child-welfare workers know little about brittle-bone disease and other conditions causing symptoms that could signal child abuse.

"The goal of these services is to protect the child, and the system often responds with an initial decision based on that protection," said Joan Zlotnik, staff director of the association's Commission on Families.

"There needs to be information out there so parents aren't wrongly accused," Zlotnik said in a telephone interview from Silver Spring. "It is hard enough for them to deal with the disease."