Stoneman Syndrome - Symptoms, Causes, Diagnosis and Treatment

Stoneman syndrome is a very rare genetic disorder that is characterized by ectopic ossification of the skeletal and connective tissues leading to progressive fusion of axial and appendicular skeleton.

Stoneman syndrome also known as Fibrodysplasia ossificans progressiva (FOP) or Münchmeyer disease, is a condition characterized by a severely disabling and catastrophic-inherited disorder of connective tissue accompanied by congenital malformation of the great toes, thumbs, and vertebrae associated with progressive ossification of striated muscles.

It is the only known medical condition where one organ system changes into another. There is no involvement of smooth muscles in this disorder and it has a low incidence report of 1 in 2 million people.

The characteristic imaging and clinical findings involved in this disorder include bilateral hallux valgus deformity, mono phalangic great toes, heterotopic ossification of muscles and connective tissues, short and broad femoral necks, short first metacarpal/metatarsals, C2-C7 facet joint fusion, large posterior elements, and tall narrow vertebral bodies. This disease condition is progressive and complicated by restriction of movements at the corresponding sites, pulmonary infections, and respiratory failure.

Cardiac and respiratory failure which results due to severe restriction of chest wall movements are the common cause of death in this condition.

Since its findings are characterized, it can be easily diagnosed with plain radiographs alone and early diagnosis would be very helpful to avoid unnecessary invasive investigations like biopsies as even trivial trauma and intramuscular injections exaggerate the progression of the disease condition with inflammation. Therefore, the knowledge of this disease condition is very important for radiologists to avoid invasive investigations.

Causes of Stoneman Syndrome

Fibrodysplasia ossificans progressiva (FOP) is caused by a mutation of the gene ACVR1. The mutation affects the body’s repair mechanism, causing fibrous tissue including muscle, tendons, and ligaments to become ossified, either spontaneously or when damaged as the result of trauma.

This mutation causes substitution of codon from arginine to histidine in the ACVR1 protein which could cause abnormal activation of ACVR1, leading to the transformation of connective tissue and muscle tissue into a secondary skeleton and then causing the endothelial cells to change into mesenchymal stem cells and then to the bone.

Stoneman Syndrome Symptoms

Generally, children born with Fibrodysplasia ossificans progressiva (FOP) often have malformed big toes, missing a joint, or sometimes, simply presented with a visible lump at the minor joint. The first “flare-up” leads to the formation of Fibrodysplasia ossificans progressiva (FOP) bone which usually occurs before the age of 10. This bone growth generally progresses from the top of the body downward, just as bones grow in fetuses.

A child with FOP will typically develop additional bones starting at the neck, then at the shoulders, arms, chest area, and finally at the feet.

There could be a restriction in the expansion of the lungs and diaphragm causing respiratory complications if there is an extra bone formation around the rib cage. Bone growth occurring during flare-ups may result in the loss of mobility to affected joints, including, if the jaw/mandible is involved, the inability to fully open the mouth, limiting speech abilities, and eating.

A specific occurrence of a flare-up of this condition in the foot/ankle joints can result in the limited ability to put a foot flat on the ground.

Diagnosis of Stoneman Syndrome

can be diagnosed with radiographs. Early diagnosis of this disorder through radiology is very important to avoid unnecessary invasive investigations like biopsies, especially since trivia trauma or intramuscular injections can amplify the progression of the disease through inflammation. This condition is often misdiagnosed as cancer or other benign entities such as infection, resulting in biopsies that can hasten disease progression.

Treatment of Stoneman Syndrome

There is no cure or approved treatment for Fibrodysplasia ossificans progressiva (FOP). However, intermittent treatments such as anti-inflammatory drugs suppress inflammation as a result of flare-ups or inflammation from bone damage.

Surgery is not possible for people with FOP as attempts to surgically remove bone in an FOP patient may result in an explosive growth of new bone. Activities that increase the risk of falling or soft tissue injury should be greatly avoided, as minor trauma could provoke the heterotopic bone formation


FOP is a rare autosomal dominant connective tissue disorder and early diagnosis is very important for genetic counseling, minimizing trauma, and painful flare-ups. Radiological investigations, especially plain radiographs, play a very vital role in the diagnosis of this condition by aiding in the identification of heterotopic ossification, the characteristic great toe changes, and other associated findings.

Therefore, radiologists must be aware of the diagnostic findings of this condition.

Egbujor Victor Chinedu
He Is Just A Pro Blogger Who Invests his time in Blogging and Web Designing ... Student, Writer...

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