A pathogenic role for brain-derived neurotrophic factor (BDNF) in fibrous dysplasia of bone

Brain derived neurotrophic factor (BDNF) is a neurotrophin, expressed in the central nervous system and in peripheral tissues, that is regulated by the Gsα/cAMP pathway. In bone, it regulates osteogenesis and stimulates RANKL secretion and osteoclast formation in osteolytic tumors such as Multiple Myeloma. Fibrous dysplasia (FD) of bone is a rare genetic disease of the skeleton caused by gain-of-function mutations of the Gsα gene in which RANKL-dependent enhanced bone resorption is a major cause of bone fragility and clinical morbidity. We observed that BDNF transcripts are expressed in human FD lesions. Specifically, immunolocalization studies performed on biopsies obtained from FD patients revealed the expression of BDNF in osteoblasts and, to a lower extent, in the spindle-shaped cells within the fibrous tissue. Therefore, we hypothesized that BDNF can play a role in the pathogenesis of FD by stimulating RANKL secretion and bone resorption. To test this hypothesis, we used the EF1α-GsαR201C mouse model of the human disease (FD mice). Western blot analysis revealed a higher expression of BDNF in bone segments of FD mice compared to WT mice and the immunolabeling pattern within mouse FD lesions was similar to that observed in human FD. Treatment of FD mice with a monoclonal antibody against BDNF reduced the fibrous tissue along with the number of osteoclasts and osteoblasts within femoral lesions. These results reveal BDNF as a new player in the pathogenesis of FD and a potential molecular mechanism by which osteoclastogenesis may be nourished within FD bone lesions. They also suggest that BDNF inhibition may be a new approach to reduce abnormal bone remodeling in FD.

Case Report: Severe McCune-Albright syndrome presenting with neonatal Cushing syndrome: navigating through clinical obstacles

Background

Café-au-lait skin macules, Cushing syndrome (CS), hyperthyroidism, and liver and cardiac dysfunction are presenting features of neonatal McCune-Albright syndrome (MAS), CS being the rarest endocrine feature. Although spontaneous resolution of hypercortisolism has been reported, outcome is usually unfavorable. While a unified approach to diagnosis, treatment, and follow-up is lacking, herein successful treatment and long-term follow-up of a rare case is presented.

Clinical case

An 11-day-old girl born small for gestational age presented with deterioration of well-being and weight loss. Large hyperpigmented macules on the trunk, hypertension, hyponatremia, hyperglycemia, and elevated liver enzymes were noted. ACTH-independent CS due to MAS was diagnosed. Although metyrapone (300 mg/m2/day) was started on the 25th day, complete remission could not be achieved despite increasing the dose up to 1,850 mg/m2/day. At 9 months, right total and left three-quarters adrenalectomy was performed. Cortisol decreased substantially, ACTH remained suppressed, rapid tapering of hydrocortisone to physiological dose was not tolerated, and supraphysiological doses were required for 2 months. GNAS analysis from the adrenal tissue showed a pathogenic heterozygous mutation. During 34 months of follow-up, in addition to CS due to MAS, fibrous dysplasia, hypophosphatemic rickets, and peripheral precocious puberty were detected. She is still regularly screened for other endocrinopathies.

Conclusion

Neonatal CS due to MAS is extremely rare. Although there is no specific guideline for diagnosis, treatment, or follow-up, addressing side effects and identifying treatment outcomes will improve quality of life and survival.

Autonomous growth hormone secretion due to McCune Albright syndrome in paediatric age group: an ominous triad

PURPOSE

The current study aimed to report cases of McCune Albright syndrome (MAS) with growth hormone (GH) hyper secretion along with a systematic review of literature to elucidate challenges and intricacies in its diagnosis and management.

METHODS

It was a single centre study carried out in individuals with MAS and autonomous GH secretion (AGHS). In addition, a systematic search of literature across three databases (PubMed, Scopus and EMBASE) was performed from inception until May 31, 2021 to identify cases of MAS with AGHS in the pediatric age group (<18 years).

RESULTS

Three cases from authors centre and 42 cases identified from systematic literature review were analysed. Precocious puberty was the most common presenting endocrinopathy seen in 56.8% (25/44) cases, followed by hyperthyroidism (10/45), hypophosphatemia (4/45), and hypercortisolism (2/45). Cranio-facial fibrous dysplasia (CFFD) was seen in all while polyostotic fibrous dysplasia and Café au lait macule was seen in 40/45 (88.9%) and 35/45 (77.8%), respectively. Pituitary adenoma (58.3% microadenoma) was localized in 53.3% (24/45) cases on pituitary imaging. Biochemical and clinical remission of AGHS was achieved in 61.5% (24/45) cases with medical therapy.

CONCLUSION

Diagnosing AGHS in MAS is challenging because of concomitant presence of CFFD, non-GH endocrinopathies associated height spurt and elevated serum IGF-1. GH-GTT should be performed in presence of elevated growth velocity and serum IGF-1 (>1 X ULN) despite adequate control of non-GH endocrinopathies. Medical management can lead to disease control in substantial number of cases and often entails use of multiple agents.

Craniofacial Fibrous Dysplasia: Clinical and Therapeutic Implications

PURPOSE OF REVIEW

This study aims to review diagnosis, potential complications, and clinical management in craniofacial fibrous dysplasia.

RECENT FINDINGS

Fibrous dysplasia (FD) is a rare mosaic disorder in which normal bone and marrow are replaced with expansile fibro-osseous lesions. Disease presents along a broad spectrum and may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). The craniofacial skeleton is one of the most commonly impacted areas in FD, and its functional and anatomical complexities create unique challenges for diagnosis and management. This review summarizes current approaches to diagnosis and management in FD/MAS, with emphasis on the clinical and therapeutic implications for the craniofacial skeleton.

Case report: Surgical treatment of McCune-Albright syndrome with hyperthyroidism and retrosternal goiter: A case report and literature review

Introduction

McCune-Albright syndrome (MAS) is a low-incidence syndrome consisting of the clinical triad of fibrous structural dysplasia of bone, endocrine disease, and skin pigmentation. Thyroid dysfunction is the second most common endocrine dysregulation in MAS. However, there are no treatment guidelines for MAS complicated with hyperthyroidism. Notably, no case of MAS complicated with retrosternal goiter and hyperthyroidism has been reported to our knowledge.

Case presentation

We report a 27-year-old man with MAS who developed the typical triad of bone fibrous dysplasia, skin pigmentation and hyperthyroidism, complaining of recent fast-growing neck mass and difficulty in breathing. Hyperthyrodism was under control by Thiamazole, and computed tomography showed an enlarged thyroid extending retrosternally. We performed a total thyroidectomy on the patient. At the 1-year follow-up, the patient's dyspnea, hyperthyroidism, and bone pain were all significantly alleviated.

Review

We searched the literature for previous case reports concerning MAS patients complicated with thyroid dysregulation. A total of 17 articles and 22 patients were identified to form our database. Among them, 9 studies clearly mentioned surgical intervention in 11 patients, and prognoses were also reported. Surgery was the most common intervention chosen and indicated a satisfactory prognosis.

Conclusion

We report a rare case of MAS patient complicated with retrosternal goiter and hyperthyroidism. Our review provides an overview of MAS cases requiring interventions on thyroid function, and total thyroidectomy should be a proper treatment for these patients.

Stigma and psychological distress among pediatric participants in the FD/MAS Alliance Patient Registry

Background

Stigma, both enacted and internalized, is part of the illness experience of many chronic conditions / diseases and has been found to increase psychological distress, lower self-esteem, and impact social engagement lowering quality of life (QOL). Stigma among pediatric patients is of particular concern due to its potential impact on identity formation. Using patient data from the online FD/MAS Alliance Patient Registry (FDMASAPR), this study seeks to 1) determine levels of enacted and self-stigma in a pediatric population of fibrous dysplasia (FD) / McCune Albright syndrome (MAS) patients and 2) to explore the relationship between stigma and anxiety and depression.

Methods

This is a cross sectional analysis of deidentified self-report data from 18 pediatric patients. Key analytic variables include the Neuro-QOL stigma short form, the Hospital Anxiety and Depression Scale (HADS), diagnostic category and craniofacial involvement, and select demographics. Sample means and score distributions are examined. Bivariate relationships between stigma, anxiety and depression and patient’s personal and medical characteristics are established through analysis of variance and correlation.

Results

Composite stigma levels for FD/MAS pediatric patients were comparable to those of children with multiple sclerosis, epilepsy, and muscular dystrophy. Self-stigma was more frequently reported than enacted/felt stigma, but few patients indicated complete freedom from either type of stigma. Diagnosis was significantly related to self-stigma. Significant bivariate relationships were found between depression and enacted/felt and self-stigma and between anxiety and self-stigma.

Conclusions

This study establishes the illness experience of pediatric patients with FD / MAS is impacted by stigma and suggests they should be regularly screened for stigma and psychological distress. It supports the integration of clinical psychologists/ therapists in regular patient care, referral of families to advocacy organizations, and indicates that rare disease patient registries can be a useful tool in efforts to improve the QOL of patients.

Assessing quality of life in pediatric fibrous dysplasia and McCune Albright syndrome: PEDS-QL and HADS data from the Fibrous Dysplasia Foundation Patient Registry

PURPOSE

The International FD/MAS Consortium recently encouraged using the Pediatric Quality of Life Inventory (PEDS-QL) and the Hospital Anxiety and Depression scales (HADS) in clinical care. This study examines scores on these measures among pediatric fibrous dysplasia and McCune Albright (FD/MAS) patients to initiate consideration of their use in clinical treatment.

METHODS

This is a retrospective analysis of pediatric data from 39 minors, ages 2-17, entered in the Fibrous Dysplasia Foundation Patient Registry from July 2016 to December 2018. Sample means and score distributions are compared to general population and chronic disease benchmarks. Associations with medical and demographic variables are also explored.

RESULTS

Mean PEDS-QL scores for children 2-7 were inconclusive in determining at risk status for impaired quality of life (QOL). Individual score distributions suggested up to half experienced extensive physical or social impairment. Means and individual score distributions for the physical and psychosocial components of the PEDS-QL for children 8-17 suggested many were at risk of impaired QOL. Over half of 13-17 year-olds met the clinical benchmark for anxiety. Older males scored better than females on the PEDS-QL and HADS. Pain frequency was associated with physical function for older children.

CONCLUSIONS

Older children with FD/MAS may be more compromised in terms of psychosocial QOL than previously reported. Clinicians should be attentive to the influence of gender on QOL in older children. Online patient registries associated with rare diseases have the potential to serve as efficient and cost-effective mechanisms to jumpstart examination of new measures in consideration for clinical use.

Regression of fibrous dysplasia in response to denosumab therapy: A report of two cases

We present two patients with fibrous dysplasia who showed a decrease in lesional size and activity after denosumab therapy. Both patients also experienced a reduction in pain and bone turnover markers, which had not been accomplished during previous bisphosphonate therapy. These cases highlight the potential of denosumab to decrease lesional size in fibrous dysplasia. This finding has been reported in mice, but not in humans. Denosumab may be considered when bisphosphonates are not tolerated or not effective (enough), or in severe cases as neoadjuvant therapy to improve surgical possibilities and outcome. In addition, these results show that Na[¹⁸F]F PET-CT is suitable for detecting change in each fibrous dysplasia lesion distinctively.

Best practice management guidelines for fibrous dysplasia/McCune-Albright syndrome: a consensus statement from the FD/MAS international consortium

Fibrous Dysplasia / McCune Albright syndrome (FD/MAS) represents a wide spectrum of diseases due to somatic gain-of-function mutations of the GNAS gene. The mutation leads to overactivity in the target tissues and to a wide phenotype of clinical features that vary in severity and age of onset. The rarity of the disease and its variable presentation to multiple specialities often leads to misdiagnosis and inappropriate variability in investigations and treatments. To address this, our international consortium of clinicians, researchers, and patients’ advocates has developed pragmatic clinical guidelines for best clinical practice for the definition, diagnosis, staging, treatment and monitoring for FD/MAS to empower patients and support clinical teams in both general and specialised healthcare settings. With the lack of strong evidence to inform care, the guidelines were developed based on review of published literature, long-standing extensive experience of authors, input from other healthcare professionals involved in the care of FD/MAS patients and feedback from patients and patient groups across the globe. This has led to the formulation of a set of statements to inform healthcare professionals, patients, their families, carers and patient groups of the best practice of care. It is anticipated the implementation of these recommendations will lead to improvement in the care of patients with FD/MAS internationally.

Peripheral precocious puberty including congenital adrenal hyperplasia: causes, consequences, management and outcomes

Peripheral precocious puberty results from peripheral production of sex steroids independent of activation of the hypothalamic-pituitary gonadal axis. It is much less common than central precocious puberty. Causes are variable and can be congenital or acquired. In this review, we will discuss the diagnosis and management of the most common etiologies including congenital adrenal hyperplasia, McCune Albright syndrome, familial male-limited precocious puberty, and adrenal and gonadal tumors.

Passive Coping Strategies Are Associated With More Impairment In Quality Of Life In Patients With Fibrous Dysplasia

Impairments in quality of life (QoL) have been reported in patients with fibrous dysplasia (FD). Here, we examine coping strategies in FD and assess whether these coping strategies are associated with QoL and disease severity. Ninety-two patients (66% females) filled out the Utrecht Coping List (UCL), Short Form-36, and the Brief Pain Inventory (BPI). Coping strategies of patients with FD were compared with reference data from a random sample of Dutch women and patients with chronic pain. Compared to healthy adults, patients expressed more emotions (p < 0.01). Compared to patients with chronic pain, patients with FD used more active coping strategies (p < 0.001), and sought more distraction (p = 0.01) and more social support (p < 0.001). Using more passive coping strategies was associated with more impairment in social function, physical role, mental health, vitality (all p < 0.001), and general health (p < 0.01). Using more avoidant coping strategies was associated with worse mental health and less vitality (both p < 0.01). More expression of emotions was associated with worse mental health (p < 0.01). Type and clinical severity of FD were not associated with coping behavior. Patients with FD have different coping strategies compared to random Dutch reference populations with or without pain. In FD, using more passive coping strategies was associated with more impairment in several aspects of QoL. There was no relationship between coping behavior and clinical characteristics, pointing to biomedical variables not determining the way patients cope with their illness. Recognition of less effective coping strategies can be helpful in the understanding and adaptation of these coping strategies, improving personalized clinical care, with the ultimate goal to improve QoL in patients with FD.

Health-related quality of life and a cost-utility simulation of adults in the UK with osteogenesis imperfecta, X-linked hypophosphatemia and fibrous dysplasia

Background

Health-related quality of life of adults with osteogenesis imperfecta (OI), fibrous dysplasia (FD) and X-linked hypophosphatemia (XLH) remains poorly described. The aim of this study was to describe the HRQoL of adults with osteogenesis imperfecta, fibrous dysplasia and X-linked hypophophataemia and perform a cost-utility simulation to calculate the maximum cost that a health care system would be willing to pay for a hypothetical treatment of a rare bone disease.

Results

Participants completed the EQ-5D-5 L questionnaire between September 2014 and March 2016. For the economic simulation, we considered a hypothetical treatment that would be applied to OI participants in the lower tertile of the health utility score.

A total of 109 study participants fully completed the EQ-5D-5 L questionnaire (response rate 63%). Pain/discomfort was the most problematic domain for participants with all three diseases (FD 31%, XLH 25%, OI 16%).

The economic simulation identified an expected treatment impact of +2.5 QALYs gained per person during the 10-year period, which led to a willing to pay of £14,355 annually for a health care system willing to pay up to £50,000 for each additional QALY gained by an intervention.

Conclusions

This is the first study to quantitatively measure and compare the HRQoL of adults with OI, FD and XLH and the first to use such data to conduct an economic simulation leading to healthcare system willingness-to-pay estimates for treatment of musculoskeletal rare diseases at various cost-effectiveness thresholds.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0538-4) contains supplementary material, which is available to authorized users.

Management of hyperthyroidism in children

Treatment of hyperthyroidism in children differs according to its etiology; in particular, the optimal therapy of Graves' disease (GD) remains a matter of debate and there is currently no evidence-based therapeutic strategy that is universally adopted in all the countries. Areas covered: The most recent treatment strategies in the different pediatric conditions which may be associated with hyperthyroidism. We searched PubMed and Cochrane (1990 to 2016) in order to identify articles to include in this review using the following terms: Hyperthyroidism, Childhood, Antithyroid drug therapy, Thyroidectomy, Radioactive iodine. Expert commentary: Although pharmacological therapy represents the first-line approach for GD children, we recommend to individualize, as much as possible, the overall therapeutic approach, with no prejudices towards radical therapies, particularly in the cases with frequent relapses. Clinical and laboratory preferential criteria for an individualized therapeutic approach to GD children are given. Treatment procedures for hyperthyroid children without GD are also discussed.

[Peripheral precocious puberty]

OBJECTIVE

To summarize literature data on peripheral precocious puberty.

DESIGN

A literature review.

SETTING

Středomoravská nemocniční a.s., hospital Šternberk, Department of Obstetrics and Gynaecology, University Hospital, Medical Faculty, Palacky University, Olomouc.

METHODS AND RESULTS

We searched in PubMed using the key words stated below according to date and published since 1980.Peripheral precocious puberty occurs in girls with the frequency 1:400-1000. It develops mainly because of peripheral estrogen secretion, the main cause of which are autonomous ovarian cysts. Other causes include McCune Albright syndrome, juvenile granulosa cell tumor and primary hypothyroidism. Typically, peripheral precocious puberty presents with early breast enlargement followed by development of other secondary sex characteristics. Initial treatment is usually conservative with the exception of juvenile granulosa cell tumor where surgery is warranted. Peripheral precocious puberty anti-estrogen therapy seems promising but neither data on its influence on fertility nor data comparing it to surgical treatment are available. Due to the risk of progression into central precocious puberty or McCune Albright syndrome, long-term follow-up is necessary.

CONCLUSION

Peripheral precocious puberty should be managed in pediatric gynecology outpatient office and often subsides spontaneously. However, it can also be a sign of malignancy. In most cases, conservative therapy is preferred with medical treatment and surgery warranted in complicated cases. However, optimal treatment has not been established yet.

A Case of Primary Hypogonadism with Features of Albright's Syndrome

BACKGROUND

McCune Albright syndrome is rare with an estimated prevalence of 1 in 100,000 to 1 in 1,000,000 persons. The classical clinical triad consists of fibrous dysplasia of the bone, café-au-lait skin spots and precocious puberty. However, in rare cases, there may be primary hypogonadism and amenorrhea.

CASE PRESENTATION

An eighteen-year-old female presented with amenorrhea. She had a short stature, round face, thick neck, and short fourth metacarpals and metatarsals. The secondary sexual characters were absent. Serum calcium, phosphorus and parathyroid concentrations were normal, but gonadotropin hormones were very low. X-ray examination revealed short fourth and fifth metacarpals, short left metatarsal, and short fibula.

CONCLUSION

These local bony abnormalities along with the biochemical findings helped us to diagnose this case as an unusual presentation of primary hypogonadism with features of McCune Albright's syndrome where there was amenorrhea rather than preocious puberty.

Benign Fibro-Osseous Lesions of the Jaws

Fibro-osseous lesions are grouped together because histologically they show similar cellular and mineralization patterns. Despite the histologic ubiquity, their behaviors vary significantly. Because of the histologic similarity and the broad range of morbidity among them, it is important to be able to differentiate between them in the preliminary diagnostic process. The radiographic presentations along with the location of the bony changes are often extremely critical diagnostic features to help render a differential or working diagnosis in lieu of an automatic biopsy procedure. Therefore the unique and specific radiographic presentations may be one of the main criteria for preliminary diagnosis.

McCune Albright syndrome in association with excessive GH secretion: case report

McCune-Albright Syndrome is a rare syndrome characterized with excessive function of peripheral endocrine organs and activating mutations of the stimulatory G protein alpha subunit are involved in the pathogenesis. The three main findings of the disease include hyperpigmented café au lait spots, fibrous dysplasia and increased endocrine functions and excessive secretion of growth hormone is observed in 21% of the patients. Clinical signs may be missed in these patients because of precocious puberty and craniofacial fibrous dysplasia. Since radiotherapy causes to sarcomatous changes and transsphenoidal surgery may cause to severe thickening in the cranial bones, they are not appropriate treatment options and medical treatment is recommended. Bromocriptine, cabergoline and octreotide or different combinations of these drugs are used in treatment and pegvisomant has also been used in recent years. Here, we present a male patient aged 12 years and 7 months to show gigantism as a rare clinical reflection of McCune-Albright Syndrome with an excessive height (197 cm), café au lait spots, growht hormone levels which could not be supressed with oral glucose tolerance test and increased prolactin levels.

Stratakis

One of the key messages of recent Salpea and Stratakis work is to underline the clinical similarities shared by these syndromes that could be explained by a defect in the same signaling pathway, i.e. activation of the cAMP pathway. That being said, we would like to emphasize that hepatopancreato-biliary lesions are one additional feature shared both by Carney complex and McCune Albright syndrome.

FGF23 and Phosphate Wasting Disorders

A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).