The Disease That Turns Muscles Into Bones

Mar 18, 2021 1 comments

Behind a glass enclosure at the Mutter Museum of The College of Physicians in Philadelphia is a terrifying exhibit—two human skeletons. Their bones appear to have melted and fused together. One of the skeletons has its back covered by sheets of bone, locking the spine to the skull, and the skull to the jaw. Additional ribbons of bone join the spine to the limbs, and immobilize the shoulders, elbows, hips, knees, and jaw. The upper arms are welded to the ribcage, and the pelvis is fused to the thigs bones. Thin stalagmites of bone launch outward from everywhere.

The deceased owners of these skeletons suffered from an extremely rare and debilitating condition called fibrodysplasia ossificans progressiva (FOP), or Münchmeyer disease. Victims suffering from FOP have their muscles, tendons, and ligaments gradually turned to bone, until the sufferer becomes rigid and unable to move.

fibrodysplasia ossificans progressiva

Anna Dhody, Mutter Museum curator, and Dr. Fred Kaplan, the world's preeminent FOP researcher, look at Carol Harry’s skeleton at the museum. Photo: Jessica Griffin/ The Philadelphia Inquirer

Normally when a person dies and the connective tissues that bind the bones together in life decomposes away, the skeleton collapses into a pile of loose bones. To display a skeleton in human form, typically in museums and in classrooms, they have to be re-articulated and pieced back together with fine wires and glue. But the two specimens at the Mutter Museum have their bones naturally and completely fused into a contiguous piece.

FOP is so rare that there are only about 700 known cases worldwide. The most famous of these patients was Harry Raymond Eastlack, whose skeleton is one of the two behind the glass façade at the Mutter Museum.

Harry Raymond Eastlack was born in 1933 in Philadelphia with characteristic malformations of the great toes, but the doctors who delivered him failed to recognize this telltale sign. When Harry was four, he was hit by a car while playing outdoors with his sister and broke his leg. The injured leg was put in a cast, but the fracture never healed properly. Months later, when the cast was removed, his leg was swollen and inflamed. Soon he found it difficult to move his hips and knees. X-rays revealed abnormal bone growths on his thighs. This later spread along his back, neck, and chest.

Harry underwent a total of eleven surgeries, but this invasive procedures only exacerbated his condition as the body tried to “repair” damaged tissues with more bones.

fibrodysplasia ossificans progressiva

The skeleton of Harry Raymond Eastlack. Photo: Joh-co/Wikimedia Commons

Despite the sufferings, Harry had a relatively happy childhood. Like any boys his age, he listened to music on the radio, loved reading, played cards with his sister, and went to the movies. At the Hamilton Theater in Philadelphia, Harry had a special seat at the center of the seventh row, where he could recline and stretch out his leg, which did not bend.

As Harry’s condition worsened, he had more difficulty with his daily activities and needed help in toileting, feeding, and dressing. At the age of 15, Harry’s jaw became fused making him unable to eat solid food. He had to speak through clenched teeth. He had difficulty siting down, as his hips were one of the first to become immobilized. Soon, bone formed across his upper arms and extended onto his breastbone, tying his arms to his chest. Sheets of bone spread along his back and ribbons of bone extended from there to his skull to lock his neck and head. Throughout the years, new bone growths caused juts of bone to form on his pelvis and thighs. One year he accidentally bumped his buttocks into a radiator, and this resulted in a bruise wherein the smooth tissue was destroyed and gave way to newly formed bone. Eventually, the only mobility that Harry was left with was in his eyes, lips, and tongue.

Harry died in 1973, just six days shy of his 40th birthday. Near the time of his death, Harry told his sister that he desired to donate his body and medical records to research, so that the disease may be further investigated and understood.

fibrodysplasia ossificans progressiva

Carol Orzel's skeleton at the Mutter Museum. Photo: Jessica Griffin/ The Philadelphia Inquirer

Fibrodysplasia ossificans progressiva, also called Stoneman disease, was first described as far back as the 17th century. By the early 20th century, only about a hundred cases were found mentioned in medical literature. Jules Rosenstirn, who conducted an extensive review of the disease, wrote:

One does not wonder that a disease so baffling it is course from the first causes to its ultimate state, should invite the speculate as well as the patiently investigating observer to lift the obscuring veil and solve this embarrassing puzzle.

It wasn’t until 2006 when researchers discovered that FOP is caused by mutations in the ACVR1 gene, and this condition can be inherited. However, in most cases, victims of FOP had no history of this frightening disorder in their family, and had developed the gene mutation spontaneously. Currently there is no cure for FOP.

In 2018, Harry Eastlack’s skeleton was joined by another skeleton, that belonging to Carol Orzel, another FOP sufferer. Like Harry, Carol too was born in Philadelphia, in 1959. She needed help with eating and dressing because she couldn’t bend her elbows. Despite her disabilities, Carol liked to draw using a stick-like device and prism eyeglasses that compensated for her immobile elbows, wrists, fingers, and neck. She drew landscapes and made greeting cards. The stick also enabled her to put on makeup. Carol loved fashion, and had an extensive wardrobe modified with Velcro and zippers to make them easy to wear.

fibrodysplasia ossificans progressiva

Carol Orzel in the early 1990s with Mary Hitner, her best friend at Inglis House.

Carol died in the same nursing home where Harry spent his last years. Carol decided to donate her body after she learnt about Harry and saw his skeleton at the Mutter Museum.

Both Harry’s and Carol’s skeletons have proven to be an invaluable source of information in the study of FOP.

# Frederick S.Kaplan, The skeleton in the closet, GENE
# Anderson Martelli and Arnaldo Rodrigues Santos, Jr, Cellular and morphological aspects of fibrodysplasia ossificans progressiva, Organogenesis
# Marie McCullough, New Mutter Museum exhibit grants final wish for woman who turned to bone, The Philadelphia Inquirer
# Wikipedia


  1. Mick Mars, guitarist from Moltey Crue, has this disease.


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