Cardiopulmonary function in fibrodysplasia ossificans progressiva

Fibrodysplasia Ossificans Progressiva: A Man Turned to Stone

Fibrodysplasia ossificans progressiva (FOP) is an exceptionally rare genetic disorder, representing humans' most debilitating form of extraskeletal ossification. It is characterized by progressive postnatal heterotopic ossification of connective tissue and malformations of the big toes. In FOP, ectopic ossification usually begins in the upper paraspinal muscles and then spreads from axial to appendicular regions, cranial to caudal directions, and proximal to distal sites. The mean life expectancy for these patients is typically 40-50 years. Most patients need partial or complete assistance with walking by age 30, and common causes of death include thoracic insufficiency syndrome and pneumonia. We present the case of a patient with an advanced stage of FOP, highlighting its complex and progressive nature. The patient exhibits severe impairment of jaw mobility, swallowing difficulties, speech impediments, and hearing impairment. Additionally, severe kyphoscoliosis, heterotopic ossification of intercostal and paravertebral muscles, and ankylosis of the spine and all major joints of the upper and lower extremities, except the metacarpophalangeal and proximal interphalangeal joints, are evident. We discuss disease presentation, current management options, and rehabilitation challenges. To our knowledge, this is the first reported case of this rare disease from our country.

Monitoring and Management of Fibrodysplasia Ossificans Progressiva: Current Perspectives

Fibrodysplasia ossificans progressiva (FOP), sometimes known as myositis ossificans progressiva, is an ultra-rare disease in which bone is formed in muscular tissue, tendons and ligaments. This is known as heterotopic ossification (HO). FOP is caused by a heterozygous mutation in the highly conserved ACVR1/ALK2 gene which affects about 1 in 1.5–2 million individuals. At birth, patients with the predominant R206H mutation only exhibit a bilateral hallux valgus. During childhood, heterotopic bone formation develops in a typical pattern, affecting the axial muscles first before appendicular body parts are involved. HO can start spontaneously but is often elicited by soft tissue trauma or medical procedures. After soft tissue injury, an inflammatory process called a flare-up can start, followed by the formation of HO. HO leads to a limited range of motion, culminating in complete ankylosis of nearly all joints. As a result of HO surrounding the thorax, patients often suffer from thoracic insufficiency syndrome (TIS). TIS is the most common cause of a limited life expectancy for FOP patients, with a median life expectancy of 56 years. Management is focused on preventing soft-tissue injury that can provoke flare-ups. This includes prevention of iatrogenic damage by biopsies, intramuscular injections and surgery. Anti-inflammatory medication is often started when a flare-up occurs but has a poor basis of evidence. Several forms of potential treatment for FOP are being researched in clinical trials. Progression of the disease is monitored using CT and 18F-NaF PET/CT combined with functional assessments. Patients are regularly evaluated for frequently occurring complications such as restrictive lung disease. Here, we review the current management, monitoring and treatment of FOP.

Deterioration of pulmonary function: An early complication in Fibrodysplasia Ossificans Progressiva

Fibrodysplasia Ossificans Progressiva (FOP) is a genetic disease characterized by the formation of heterotopic ossification (HO) in connective tissues. HO first develops in the thoracic region, before more peripheral sites are affected. Due to HO along the thoracic cage, its movements are restricted and pulmonary function deteriorates. Because development of HO is progressive, it is likely that pulmonary function deteriorates over time, but longitudinal data on pulmonary function in FOP are missing. Longitudinal pulmonary function tests (PFTs) from seven FOP patients were evaluated retrospectively to assess whether there were changes in pulmonary function during aging. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), total lung capacity (TLC), residual volume (RV) and diffusing lung capacity for carbon dioxide divided by alveolar volume (DLCO/VA) were included. In addition, HO volume along the thorax together with its progression as identified by whole body low dose CT scans were correlated to PFT data. Per patient, aged 7-57 years at the time of the first PFT, three to nine PFTs were available over a period of 6-18 years. Restrictive pulmonary function, identified by TLC or suspected by FVC, was found in all, but one, patients. In three patients, TLC, FVC or both decreased further during the follow-up period. All, but one, patients had an increased RV. The DLCO/VA ratio was normal in all FOP patients. Interestingly, FEV1 increased after a surgical intervention to unlock the jaw. In four out of five patients total HO volume in the thoracic region progressed beyond early adulthood, but no further decline in FVC was observed. In conclusion, restrictive pulmonary function was found in the majority of patients already at an early age. Our data suggest that the deterioration in pulmonary function is age dependent.

When Limb Surgery Has Become the Only Life-Saving Therapy in FOP: A Case Report and Systematic Review of the Literature

Fibrodysplasia ossificans progressiva (FOP) is a rare disease in which heterotopic ossification (HO) is formed in muscles, tendons and ligaments. Traumatic events, including surgery, are discouraged as this is known to trigger a flare-up with risk of subsequent HO. Anesthetic management for patients with FOP is challenging. Cervical spine fusion, ankylosis of the temporomandibular joints, thoracic insufficiency syndrome, restrictive chest wall disease, and sensitivity to oral trauma complicate airway management and anesthesia and pose life-threatening risks. We report a patient with FOP suffering from life-threatening antibiotic resistant bacterial infected ulcers of the right lower leg and foot. The anesthetic, surgical and postoperative challenges and considerations are discussed. In addition, the literature on limb surgeries of FOP patients is systemically reviewed. The 44 year-old female patient was scheduled for a through-knee amputation. Airway and pulmonary evaluation elicited severe abnormalities, rendering standard general anesthesia a rather complication-prone approach in this patient. Thus, regional anesthesia, supplemented with intravenous analgosedation and N₂O-inhalation were performed in this case. The surgery itself was securely planned to avoid any unnecessary tissue damage. Postoperatively the patient was closely monitored for FOP activity by ultrasound and [¹⁸F]PET/CT-scan. One year after surgery, a non-significant amount of HO had formed at the operated site. The systematic review revealed seventeen articles in which thirty-two limb surgeries in FOP patients were described. HO reoccurrence was described in 90% of the cases. Clinical improvement due to improved mobility of the operated joint was noted in 16% of the cases. It should be noted, though, that follow-up time was limited and no or inadequate imaging modalities were used to follow-up in the majority of these cases. To conclude, if medically urgent, limb surgery in FOP is possible even when general anesthesia is not preferred. The procedure should be well-planned, alternative techniques or procedures should be tested prior to surgery and special attention should be paid to the correct positioning of the patient. According to the literature recurrent HO should be expected after surgery of a limb, even though it was limited in the case described.

Restricted Mandibular Movement Attributed to Ossification of Mandibular Depressors and Medial Pterygoid Muscles in Patients With Fibrodysplasia Ossificans Progressiva: A Report of 3 Cases

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare genetic condition characterized by congenital malformation and progressive heterotopic ossification (HO) caused by a recurrent single nucleotide substitution at position 617 in the ACVR1 gene. As the condition progresses, HO leads to joint ankylosis, breathing difficulties, and mouth-opening restriction, and it can shorten the patient's lifespan. This report describes 3 cases of FOP confirmed by genetic testing in patients with restricted mouth opening. Each patient presented a different onset and degree of jaw movement restriction. The anatomic ossification site of the mandibular joint was examined in each patient using reconstructed computed tomographic (CT) images and 3-dimensional reconstructed CT (3D-CT) images. A 29-year-old woman complained of jaw movement restriction since 13 years of age. 3D-CT image of the mandibular joint showed an osseous bridge, formed by the mandibular depressors that open the mouth, between the hyoid bone and the mentum of the mandible. A 39-year-old man presented with jaw movement restriction that developed at 3 years of age after a mouth injury. 3D-CT image of the jaw showed ankylosis of the jaw from ossification of the mandibular depressors that was worse than in patient 1. CT images showed no HO findings of the masticatory muscles. To the authors' knowledge, these are the first 2 case descriptions of the anatomic site of ankylosis involving HO of the mandibular depressors in the jaw resulting from FOP. In contrast, a 62-year-old bedridden woman with an interincisal distance longer than 10 mm (onset, 39 years of age) had no HO of the mandibular depressors and slight HO of the medial pterygoid muscle on the right and left sides. These findings suggest that restricted mouth opening varies according to the presence or absence of HO of the mandibular depressors.

Emergent airway management in a case of fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP), or Stone man syndrome, is rare and one of the most disabling genetic conditions of the connective tissue due to progressive extraskeletal ossification. It usually presents in the first decade of life as painful inflammatory swellings, either spontaneously or in response to trauma, which later ossify and lead to severe disability. Progressive spinal deformity including thoracolumbar kyphoscoliosis leads to thoracic insufficiency syndrome, increasing the risk for pneumonia and right sided heart failure. We present the airway management in a 22-year-old male, diagnosed with FOP with severe disability, who required urgent airway intervention as a result of respiratory failure from pnuemonia. Tracheostomy triggers ossification and consequent airway obstruction at the tracheostomy site and laryngoscopy triggers temporomandibular joint ankylosis. Therefore, awake fiber-optic endotracheal intubation is recommended in these patients. Use of an airway endoscopy mask enabled us to simultaneously maintain non-invasive ventilation and intubate the patient in a situation where tracheostomy needed to be avoided.

General anesthesia in fibrodysplasia ossificans progressive: a case report and clinical review

Fibrodysplasia ossificans progressiva (FOP) is a rare and devastating genetic disorder of connective tissue characterized by heterotopic bone formation and progressive musculoskeletal disability. Soft-tissue trauma may exacerbate this condition and lead to further ossification. We described the anesthetic and perioperative management of a 23-year-old male with FOP scheduled for dental extraction requiring general anesthesia. Preoperative examination revealed multisystem involvement including cranial and cervical ankylosis and severe restrictive lung disease. Nasal fiber-optic endotracheal intubation was chosen in our patient. Anesthesia was maintained with total intravenous anesthesia and ventilation was controlled throughout the surgery. Endotracheal tube was remained for mechanical ventilation until the second postoperative day and aggressive respiratory physiotherapy was performed after extubation. Additionally, extreme caution was taken to a femoral vascular access and an arterial catheter. Positioning of the patient was meticulous and air warming blanket was used to minimize soft tissue trauma. No significant documented intraoperative and postoperative adverse events appeared attributable to the anesthesia.

Biopsy diagnosis of early myositis ossificans without radiologic evidence of calcification: success of early surgical resection

Myositis ossificans is an uncommon disorder, which is commonly mistaken for a malignant muscle disease before histologic examination. Trauma is the most common cause of the acquired form of the disease; however, atraumatic cases have been described. The factors responsible for extraosseous ossification, such as the role of bone morphogenic protein 4, are becoming better understood. However, treatment of the disorder is not well defined. We present a case of atraumatic myositis ossificans in a 16-year-old girl that was associated with severe pain and lacked radiologic evidence of calcification. She underwent early surgical excision, resulting in immediate resolution of her symptoms. This case demonstrates that waiting for complete maturation of the lesion may not be necessary.

Early mortality and cardiorespiratory failure in patients with fibrodysplasia ossificans progressiva

BACKGROUND

Fibrodysplasia ossificans progressiva, a rare genetic disorder of progressive extraskeletal ossification, is the most disabling form of heterotopic ossification in humans. However, little is known about the lifespan or causes of mortality in these patients. We undertook this study to determine the lifespan and causes of mortality in individuals who had fibrodysplasia ossificans progressiva.

METHODS

We reviewed comprehensive mortality reports from two large registries of patients with fibrodysplasia ossificans progressiva. Together, these registries comprise >90% of all known patients with this condition in the world. We noted the sex, dates of birth and death, and the cause of death for each individual. We verified the cause of death with extensive medical records, when available. We also collected date of birth, current age, and sex information for each living patient member of the International Fibrodysplasia Ossificans Progressiva Association.

RESULTS

Sixty deaths (thirty male and thirty female patients) were reported in the fibrodysplasia ossificans progressiva community during a thirty-three-year-period. For all sixty patients, the median age at the time of death was forty years (range, three to seventy-seven years). Data were sufficient to establish the cause of death in forty-eight (80%) of the sixty individuals. The median age at the time of death for the forty-eight patients (twenty-four male and twenty-four female patients) with an established cause of death was also forty years. The median lifespan estimated from the 371 individuals in the international fibrodysplasia ossificans progressiva community who were alive and the sixty who had died was fifty-six years (95% confidence interval, fifty-one to sixty years). The most common causes of death in patients with fibrodysplasia ossificans progressiva were cardiorespiratory failure from thoracic insufficiency syndrome (54%; median age, forty-two years) and pneumonia (15%; median age, forty years).

CONCLUSIONS

Fibrodysplasia ossificans progressiva is not only an extremely disabling disease but also a condition of considerably shortened lifespan. The most common cause of death in patients with fibrodysplasia ossificans progressiva is cardiorespiratory failure from thoracic insufficiency syndrome.

Anaesthetic management of a child with fibrodysplasia ossificans progressiva

Fibrodysplasia Ossificans Progressiva (FOP) is a rare inherited disease in which progressive ossification of striated muscles leads to severe disability and respiratory impairment early in life and there are associated characteristic congenital skeletal malformations. Although this condition may prove demanding for the anaesthetist, few reports are available regarding anaesthesia in paediatric patients. We review the clinical features of the disease relevant to anaesthesia and describe the perioperative care of an 18-month-old boy with FOP who underwent endoscopic third-ventriculostomy for hydrocephalus associated with a brainstem mass. We emphasize the importance of an appropriate anaesthetic management of these patients, as inadequate care may lead to exacerbation of the disease with permanent sequelae.

Bone morphogenetic protein-4 regulation in fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva is a rare genetic disorder in which connective tissues are replaced with heterotopic bone through an endochondral process. Bone morphogenetic protein-4 messenger ribonucleic acid and protein levels are elevated in the cells of patients with fibrodysplasia ossificans progressiva, but the molecular mechanism of this steady-state elevation is unknown. Nuclear run-on assays and messenger ribonucleic acid stability assays were done to examine the molecular mechanisms of increased bone morphogenetic protein-4 messenger ribonucleic acid. The bone morphogenetic protein-4 transcription rate in patient cells was found to be enhanced fivefold to sevenfold over normal control cells, suggesting that elevated steady-state levels of this transcript were attributable at least in part to an enhancement in transcription initiation. The stability of bone morphogenetic protein-4 messenger ribonucleic acid was found to be similar for patient and control cells and to have an extremely brief half-life, with bone morphogenetic protein-4 messenger ribonucleic acid almost completely decayed (75%) by 40 minutes. This unusually brief half-life suggests that a high fidelity control over temporal expression of the bone morphogenetic protein 4-message can be maintained. The data document that enhanced transcription rather than increased messenger ribonucleic acid stability is responsible for the elevation in steady-state levels of bone morphogenetic protein-4 messenger ribonucleic acid, and suggest that an inappropriate enhancement of the rate of bone morphogenetic protein-4 transcription plays a critical role in the molecular pathophysiology of fibrodysplasia ossificans progressiva.

Linkage exclusion and mutational analysis of the noggin gene in patients with fibrodysplasia ossificans progressiva (FOP)

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare and disabling genetic disorder characterized by congenital malformation of the great toes and by progressive heterotopic endochondral ossification in predictable anatomical patterns. Although elevated levels of bone morphogenetic protein 4 (BMP4) occur in lymphoblastoid cells and in lesional cells of patients with FOP, mutations have not been identified in the BMP4 gene, suggesting that the mutation in FOP may reside in a BMP4-interacting factor or in another component of the BMP4 pathway. A powerful antagonist of BMP4 is the secreted polypeptide noggin. A recent case report described a heterozygous 42-bp deletion in the protein-coding region of the noggin gene in a patient with FOP. In order to determine if noggin mutations are a widespread finding in FOP, we examined 31 families with 1 or more FOP patients. Linkage analysis with an array of highly polymorphic microsatellite markers closely linked to the noggin gene was performed in four classically-affected multigenerational FOP families and excluded linkage of the noggin locus to FOP (the multipoint lod score was -2 or less throughout the entire range of markers). We sequenced the noggin gene in affected members of all four families, as well as in 18 patients with sporadic FOP, and failed to detect any mutations. Single-strand conformation polymorphism (SSCP) analysis of 4 of these patients plus an additional 9 patients also failed to reveal any mutations. Among the samples analyzed by SSCP and DNA sequencing was an independently obtained DNA sample from the identical FOP patient previously described with the 42-bp noggin deletion; no mutation was detected. Examination of the DNA sequences of 20 cloned noggin PCR products, undertaken to evaluate the possibility of a somatic mutation in the noggin gene which could be carried by a small subset of white blood cells, also failed to detect the presence of the reported 42-bp deletion. We conclude that mutations in the coding region of noggin are not associated with FOP.

Fibrodysplasia ossificans progressiva in two half-sisters: evidence for maternal mosaicism

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder of connective tissue characterized by congenital malformation of the great toes and by progressive heterotopic ossification of the soft tissues in specific anatomic and temporal patterns. We observed classic findings of FOP in 2 Native American half-sisters with the same unaffected mother and different unaffected fathers. This is the first report of FOP in sibs from different pregnancies with unaffected parents. The findings in this family indicate the possibility of maternal gonadal mosaicism in FOP and provide important new data for genetic counseling in this disease.

Fibrodysplasia (myositis) ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP) is a rare hereditary connective tissue disorder. Patients with FOP develop progressive ossification of muscle and connective tissue associated with pain and disability. Onset is typically in childhood, and congenital anomalies of the feet are an early sign of this condition. Pain and stiffness of the spine or an inflammatory mass are common presenting features of FOP. Involvement of the spine often leads to complete fusion mimicking ankylosing spondylitis. Studies of twins and families suggest that FOP is a genetically inherited autosomal dominant trait with complete penetrance but variable expressivity. While radionuclide imaging and computed tomography are very sensitive for new bone formation and greatly assist the diagnosis of FOP, unfortunately, effective therapy is unavailable. We present twins with FOP and review the clinical, radiographic, and genetic manifestations of this disorder.

Heterotopic Ossification: Two Rare Forms and What They Can Teach Us

Heterotopic ossification is characterized by the formation of normal bone at ectopic soft-tissue locations. Regardless of the etiology of heterotopic ossification, requisite pathogenetic conditions include an inductive signal capable of stimulating morphogenesis, a population of inducible osteoprogenitor cells, and a heterotopic environment conducive to osteogenesis. Two rare heritable and developmental forms of heterotopic ossification, fibrodysplasia ossificans progressiva and progressive osseous heteroplasia, provide valuable clinical and pathogenetic insights into heterotopic ossification in humans. A fundamental understanding of the developmental and molecular pathology of these disorders may lead to more effective strategies for preventing and treating heterotopic ossification in humans.

Spinal deformity in patients who have fibrodysplasia ossificans progressiva

We reviewed roentgenograms and clinical records in order to characterize the spinal deformity in forty patients who had an established diagnosis of fibrodysplasia ossificans progressiva. Twenty-six (65 per cent) of the patients had scoliosis, which, according to the clinical records and the recollection of the patients, had been present during childhood. Twenty-three (88 per cent) of the twenty-six curves were unbalanced c-shaped curves, while the remaining three (12 per cent) were balanced s-shaped curves. Twenty-one (91 per cent) of the twenty-three c-shaped curves involved the thoraco-lumbar or lumbar spine. The c-shaped curves ranged in magnitude from 15 to more than 80 degrees. Curves became rigid by early adulthood and many resulted in severe pelvic obliquity with impaired sitting or standing balance. An osseous bridge developed between the posterolateral aspect of the iliac crest and the posterolateral aspect of the rib cage in twenty-two (55 per cent) of the forty patients. Nineteen (86 per cent) of these twenty-two patients had scoliosis; there was a significant association between the development of scoliosis and the presence of the osseous bridge (p < 0.005). Ossification of the paravertebral muscles and fascia during the first decade of life limited the development of a normal thoracic kyphosis in ten (42 per cent) of twenty-four patients for whom lateral roentgenograms of the spine were available. A spinal orthosis was used to treat the scoliosis in two patients, but this method resulted in breakdown of the skin and failed to halt progression of the curve.(ABSTRACT TRUNCATED AT 250 WORDS)

The natural history of heterotopic ossification in patients who have fibrodysplasia ossificans progressiva. A study of forty-four patients

Forty-four patients who had fibrodysplasia ossificans progressiva responded by mail to a questionnaire regarding the age at the onset of heterotopic ossification at fifteen commonly involved anatomical sites. The average age of the patients when they responded to the questionnaire was twenty-seven years (range, three to sixty-nine years). The average age at the onset of ossification was five years (range, birth to twenty-five years). The most common sites of early heterotopic ossification were the neck, spine, and shoulder girdle. Thirty-five (80 per cent) of the patients had had some restrictive heterotopic ossification by the age of seven years. By the age of fifteen years, forty-two (more than 95 per cent) of the patients had severely restricted mobility of the upper limbs. In these patients, heterotopic ossification proceeded in a direction that was axial to appendicular, cranial to caudad, and proximal to distal; this pattern appeared typical for fibrodysplasia ossificans progressiva.

Anesthesia in 'stone man': myositis ossificans progressiva

Myositis ossificans progressiva is a rare disease leading to complete ossification of the muscular system. Very little information about this rare disease and its anesthetic implications has appeared in anesthetic literature. This disease is felt to have an autosomal dominant pattern of inheritance and is usually associated with anomalies of the hands and feet. Afflicted patients are frequently misdiagnosed in childhood as having a rheumatologic disorder. Later in life (as true bone is formed in striated muscle, ligaments, and fascia), the correct diagnosis becomes obvious. Although muscles of the heart, diaphragm, larynx, and sphincters are spared, those of the chest wall are not, and pulmonary function progressively deteriorates. Death frequently occurs as a result of a pulmonary infection. Specific anesthetic considerations include positioning to avoid injury, potential need for fiberoptic intubation or tracheostomy, decreased thoracic compliance with the need for increased ventilating pressures, and the ultimate in disuse atrophy contraindicating the use of succinylcholine. Myositis ossificans progressiva can present the anesthesiologist with interesting challenges. Anesthetic management will need to be individualized according to the severity of the disease.

Genetic aspects of fibrodysplasia ossificans progressiva

Complete ascertainment of fibrodysplasia ossificans progressiva in the United Kingdom was attempted and 44 patients were identified. This indicates a point prevalence of 0.61 x 10(-6). The disease is determined as an autosomal dominant trait which has complete penetrance but variable expressivity. No evidence for genetic heterogeneity was found in this series. All patients represented fresh gene mutations and their biological fitness was zero. Geographical clustering of these new mutations was evident but conformed to the general population distribution. The direct estimate of the mutation rate was 1.8 (SE +/- 1.04) x 10(-6) mutations per gene per generation. A significant paternal age effect was evident for these new mutations in the United Kingdom.