Erratum: Maternal GNAS contributes to the extra-large G protein α-subunit (XLαs) expression in a cell type-specific manner.

[This corrects the article DOI: 10.3389/fgene.2021.680537.].

Craniofacial fibrous dysplasia: Systematic review of facial management.

Craniofacial fibrous dysplasia (CFD) may be associated with major cosmetic or functional consequences. However, management recommendations for CFD are currently unavailable. Therefore, this systematic literature review aimed to review the existing approaches for CFD management and propose a management algorithm. The focus question was "What are the different options for CFD treatment and their complication rates?" The MEDLINE database was searched, and 33 articles evaluating a total of 1154 patients were reviewed. The bias assessment showed that 20 of the 33 studies had a high or intermediate risk of bias, mainly because of retrospective data collection and small patient numbers. Radical surgery showed a lower recurrence rate than debulking, but its use should be weighed against the morbidity caused by the reconstruction performed in this technique. Orbital decompression using a radical technique or debulking is effective in cases showing exophthalmos or dystopia. Surveillance is a viable option for asymptomatic and/or non-progressive lesions. In cases showing optic nerve compression, prophylactic decompression should be avoided, and decompression should be performed only when patients show diminished visual acuity or visual field defect. Although bisphosphonates have shown efficacy in pain management, their posology requires further discussion. A management algorithm is presented.

Alveolar Bone Box Ostectomy Grafted with Particulate Bone Substitute with Subsequent Dental Implant Placement in a Case of Craniofacial Fibrous Dysplasia Involving the Posterior Maxilla: Case Report and Literature Review.

BACKGROUND: Patients with dysplastic bone diseases, including fibrous dysplasia (FD), represent a particular challenge for placement of dental implants. This is due to structural bony changes that may compromise the bone blood supply and plasticity, thus potentially affecting the process of osseointegration. This case report describes a novel approach for dental-implant-based rehabilitation of the posterior maxilla affected by craniofacial fibrous dysplasia (CFD), with 7 years of treatment follow-up. CASE PRESENTATION: A 35-year-old female patient was referred due to a suspected unidentified bone lesion affecting the left side of the maxilla. A clinical and radiographic diagnosis of fibrous dysplasia was confirmed through a wedge bone biopsy. Particulate bone substitute was packed into a box-shaped ostectomy area of the lesion in the affected maxillary alveolar ridge. This was followed by the placement of four implants 6 months post operation. The implants were successfully integrated, as confirmed by clinical examination over 7 years of follow up. CONCLUSION: this treatment approach may be considered as a predictable and efficient treatment modality for dental implant rehabilitation in patients with a variety of fibro-osseous lesions, including fibrous dysplasia, which affect the alveolar bone.

Diagnosis and treatment of McCune-Albright syndrome: A case report.

BACKGROUND: McCune-Albright syndrome (MAS) is extremely rare clinically. We here report a case of MAS with severe symptoms that have not been reported previously. CASE SUMMARY: A 10-year-old boy attended our outpatient clinic due to craniofacial malformations found two years ago. He underwent temporal bone computed tomography and digital radiography photography. Based on a literature review combined with the patient's medical history and imaging examination findings, he was diagnosed with multiple fibrous dysplasia of bone. As the clinical symptoms related to MAS in this patient were not obvious, he was only followed up and not given any special treatment. CONCLUSION: The unique clinical manifestations in this MAS patient may be related to mutations in the GNAS gene.

Multimodal imaging diagnosis for bone fibrous dysplasia malignant transformation: A case report.

Fibrous dysplasia of bone (FDB) is a rare benign condition in which fibrous tissue replaces normal bone architecture. FDB rarely undergoes malignant transformation, but there are reports of locally aggressive fibrous dysplasia with cortical destruction and soft tissue extension. Diagnosis of FDB malignant transformation is not easy, especially in monostotic form, because of the overlap in imaging features of locally aggressive fibrous dysplasia and fibrous dysplasia with malignant transformation. The present case study reports a rare case of FDB in a 23-year-old man with polyostotic fibrous dysplasia arising in the left side of the pelvis and lower limb bones with partial transformation to fibrosarcoma. This study explored the multimodal imaging features of FDB malignant transformation, to achieve early detection and improve diagnostic accuracy of local FDB aggressiveness and its malignant transformation.

Value of rare diseases reference centers: impact on diagnosis and access to specialized care in fibrous dysplasia of bone.

INTRODUCTION: Reference Centers and Rare Disease Health Networks aim to improve the management of patients with rare diseases. The French reference center for Fibrous Dysplasia was certified in 2006. OBJECTIVE: The objective of our study was to assess the effectiveness of our reference center since its constitution. METHODS: In a retrospective cohort study, we compared the activity of our center, including the time elapsed between access to the center and the diagnostic delay of patients with Fibrous Dysplasia between two periods, 1994-2006 (before certification) and 2007-2019 (after certification). Data were extracted from patients' records (Easily®). Wilcoxon and Fisher tests were performed, using R®. RESULTS: Our cohort included 527 patients with Fibrous Dysplasia/Mc Cune Albright syndrome. The activity of the Fibrous Dysplasia center increased from 139 patients in the first period (1994-2006) to an additional 388 patients for the second period (2007-2019). Mean time elapsed to diagnosis of Fibrous Dysplasia was 1.5 years before 2007 and 1.9 years after 2007 (p = 0.12). Diagnosis was made before referral in over 80% of patients. There was a non-significant decrease in the number of patients with delayed diagnosis: 37 patients (44%) in the first period had a diagnostic delay and 94 patients (33%) in the second period (p = 0.07). Patients were referred to our center on average 6.8 years (before 2007) and 7.9 years (after 2007) after their diagnosis (p = 0.77). CONCLUSION: Healthcare organization with reference centers significantly impacted the management of patients with Fibrous Dysplasia/Mc Cune Albright syndrome, with a substantial increase in the activity of our center, that roughly tripled since certification. This healthcare organization was also associated with a trend toward decreasing diagnostic delay. However, diagnostic delay affected more than a third of patients and the time to access to the center remained extended (≈7-8 years after diagnosis). The current challenge lies in informing primary care providers and patients about education to rare diseases and existence of reference centers for earlier and more effective specialized management.

Bilateral total hip arthroplasty in a case with fibrous dysplasia: a case report.

BACKGROUND: Fibrous dysplasia (FD) is a benign neoplasm with a broad spectrum of presentations. The treatment of FD in the hip region is controversial among orthopedic surgeons. Several treatment options exist, including curettage and grafting, valgus osteotomy, medial displacement osteotomy, and so on. Performing total hip arthroplasty (THA) on these patients and their subsequent outcome is still in infancy. CASE PRESENTATION: The patient is a 32-year-old white female with bilateral proximal femur FD who underwent bilateral THA with long stem implants. A year following surgery, she had no complications and had satisfactory radiological, pain, and functional outcomes. CONCLUSION: A bilateral THA with a long stem prosthesis showed promising results when performed following appropriate curettage of the proximal bone in an FD case. A cementless long stem could have enabled better diaphyseal fixation distal to the lesion site.

Efficacy of antiresorptive agents in fibrous dysplasia and McCune Albright syndrome, a systematic review and meta-analysis.

Fibrous dysplasia (FD) is a rare skeletal disorder in which normal bone is replaced by a fibro-osseous tissue, resulting in possible deformities and fractures. The aim of this systematic review and meta-analysis was to synthesize the available evidence on the use of antiresorptive drugs in FD in terms of changes in bone turnover markers (BTMs), bone mineral density (BMD), and reducing pain. Three databases were searched in October 2022, with an update in July 2023. Of the 1037 studies identified, 21 were retained after eligibility assessment. A random-effects model was used to calculate global effect size and the corresponding standard error. Pamidronate and Denosumab were the most reported drugs in a total of 374 patients assessed. The initiation of treatments was accompanied by an average reduction of 40.5% [CI95% -51.6, -29.3] in the bone resorption parameters, and 22.0% [CI95% -31.9, -12.1] in the parameters of bone formation after 6-12 months. BMD was increased in both FD lesions and in the unaffected skeleton. Pain was reduced by 32.7% [CI95% -52.7, -12.6] after 6-12 months of treatment, and by 44.5% [CI95% -65.3, -23.6] after a mean 41.2 months of follow-up. The variation in pain was highly correlated to variation in bone resorption (R2 = 0.08, p < 0.0001) and formation parameters (R2 = 0.17, p < 0.0001). This study supports the overall efficacy of antiresorptive therapies in terms of reducing bone remodeling, improving bone density, and pain in FD.

Refractory and progressively worsening nasal obstruction: case report of nasal osteoblastoma and literature review.

Nasal osteoblastoma (OB) is a rare and locally aggressive osteogenic tumor that has rarely been reported, and there is a lack of effective evidence data for its diagnosis and treatment. In this study, we report a 31-year-old female patient who presented with nasal congestion and associated progressive painless swelling of the left maxillofacial region. A preoperative computed tomography (CT) examination of the paranasal sinuses was performed, and based on the imaging presentation, the surgeon was unable to differentiate between OB, osteoid osteoma (OO), fibrous dysplasia of bone (FDB) and osteoblastic fibroma (OF). After excluding contraindications to surgery, the patient underwent nasal endoscopic excision of the left nasal mass, which was found to be gravel-like and difficult to remove cleanly during the operation. The mass was brittle and bled easily, resulting in inadequate exposure of the operative field, prolonged operation time, and substantial intraoperative blood loss. This indicates that definite preoperative diagnosis (biopsy of deeper parts of the mass is recommended) and appropriate preoperative preparations (e.g., preoperative angiography and embolization, adequate blood preparation) are very important. The intraoperative frozen and postoperative pathological results clearly identified the tumor as OB. No local recurrence of the tumor was observed at the 11-month postoperative follow-up.

Brain and eye involvement in McCune-Albright Syndrome: clinical and translational insights.

McCune-Albright Syndrome (MAS) is a rare mosaic (post-zygotic) genetic disorder presenting with a broad continuum clinical spectrum. MAS arises from somatic, activating mutations in the GNAS gene, which induces a dysregulated Gsα-protein signaling in several tissues and an increased production of intracellular cyclic adenosine monophosphate (cAMP). Overall, MAS is a rare disorder affecting less than 1/100,000 children and, for this reason, data establishing genotype-phenotype correlations remain limited. Affected individuals clinically present with a variable combination of fibrous dysplasia of bone (FD), extra-skeletal manifestations (including cafeí-au-lait spots) and precocious puberty which might also be associated to broad hyperfunctioning endocrinopathies, and also gastrointestinal and cardiological involvement. Central nervous system (CNS) and eye involvement in MAS are among the less frequently described complications and remain largely uncharacterized. These rare complications mainly include neurodevelopmental abnormalities (e.g., delayed motor development, cognitive and language impairment), CNS anomalies (e.g., Chiari malformation type I) and a wide array of ophthalmological abnormalities often associated with vision loss. The pathophysiological mechanisms underlying abnormal neurological development have not been yet fully elucidated. The proposed mechanisms include a deleterious impact of chronically dysregulated Gsα-protein signaling on neurological function, or a secondary (damaging) effect of (antenatal and/or early postnatal) hypercortisolism on early pre- and post-natal CNS development. In this Review, we summarize the main neurological and ophthalmological features eventually associated with the MAS spectrum, also providing a detailed overview of the potential pathophysiological mechanisms underlying these clinical complications.

Nonspecific Cystic Degeneration in Craniofacial Fibrous Dysplasia: A Rare Finding.

Fibrous dysplasia (FD) is a developmental pathology of the bones in which normal bone is replaced by fibrous tissue and immature bone. It can affect single bone (monostotic) or multiple bones (polyostotic), sporadically or in association with McCune-Albright syndrome, Jaffe-Lichtenstein syndrome, or Mazabraud syndrome. When multiple bones in the craniofacial region are affected, the term "craniofacial FD" is used. Nonspecific cystic degeneration occurring in FD of the jaws has rarely been reported in the literature. Here, we present a 52-year-old male patient who reported with a longstanding gradual expansion of the mandible unilaterally. Investigations revealed the presence of mixed radiolucent radioopaque appearance in the mandible and dense sclerotic multiple craniofacial bones. In addition, a lytic lesion in the mandible was appreciated. Histopathological examination of the mandible confirmed the diagnosis of FD with nonspecific cystic degeneration.

[Clinicopathological analysis of 105 patients with fibrous dysplasia of cranio-maxillofacial region].

OBJECTIVE: To compare the clinicopathologic features and prognosis of the different types of fibrous dysplasia (FD) of cranio-maxillofacial region, so as to provide a new reference for clinicians to treat these patients and make prognostic judgement. METHODS: Clinical records, radiographic data and pathological information of 105 patients diagnosed with FD or McCune-Albright syndrome (MAS) at the Department of Oral Pathology, Peking University Hospital of Stomatology from January 2013 to December 2020 were collected. The patients were divided into 4 groups: monostotic FDs, polyostotic FDs, MAS and a specific type called craniofacial fibrous dysplasia (CFD) limited in the craniofacial region. The clinicopathological characteristics, treatment and follow-up data of each type were analyzed. RESULTS: Of all the 105 patients, 46 were males and 59 were females, with a male-to-female ratio of 1 ∶1.3. The onset age ranged from 0 to 56 years and the median age was 12 years. On the basis of different involvement conditions, 4 types were divided. The most common type was monostotic FDs (43 cases, 40.95%), including maxilla (29 cases), mandibular (12 cases) and zygoma (2 cases). 32 cases (30.48%) were diagnosed with polyostotic FDs, 7 cases (6.67%) were MAS, and 23 cases (21.90%) were CFDs confirmed by computed tomography (CT) analysis. CFD was clearly distinct from other types of FD, such as the patient gender and the serum alkaline phosphatase level in peripheral blood before operative surgery. The pathologic findings of various types FD were quite similar, whilst the predominant fibrous tissue hyperplasia could be observed in polyostotic FDs and MAS types. CONCLUSION: The clinicopathologic features of FD in the cranio-maxillofacial region are different from the FD lesions in other parts of the body. The clinicopathological features of CFD are significantly different from those of monostotic and polyostotic FDs in the cranio-maxillofacial region. Therefore, the clinicians should pay attention to distinguish CFD in clinic, imaging and pathology aspects, so as to further clarify its features in clinic management and prognosis.

Inhibition of IL-6 in the treatment of fibrous dysplasia of bone: The randomized double-blind placebo-controlled TOCIDYS trial.

Increased interleukin-6 (IL-6) has been observed in the bone tissue of fibrous dysplasia of bone/McCune-Albright syndrome (FD/MAS) and is possibly involved in the increased bone destruction and bone pain characterizing this disease. The TOCIDYS trial was a randomized, placebo-controlled, 1 year, cross-over, proof-of-concept trial, conducted in patients not responding to bisphosphonates, using monthly intra-venous tocilizumab (a monoclonal antibody to the IL-6 receptor) at 8 mg/kg or a matching placebo for 6 months. Over the following 6 months, they received tocilizumab if they first had placebo, and vice-versa. We measured change in serum CTX after 6 months of treatment, compared with baseline (primary endpoint). Other endpoints were the change in bone pain, change in P1NP, bone alkaline phosphatase, osteocalcin and ICTP, and variation of quality of life. The analysis relied on ANOVA, with sequence of treatment, period and treatment as factors and accounting for a potential carry-over effect. We have randomized 8 patients with FD/MAS in each sequence who all completed the first 6 months treatment period. During the second 6 months period, 3 patients stopped therapy, so the efficacy analysis set included 13 patients. We observed no significant change in serum CTX and other biochemical markers of bone turnover between the tocilizumab and placebo groups. There was no significant change in the level of bone pain on tocilizumab, although 3 patients had a sharp decrease in pain while on active drug, with progressive relapse on placebo for 2 of them, but with some degree of improvement in a few patients while on placebo. The SF-36 quality of life scale was not significantly changed. We conclude that tocilizumab does not decrease bone turnover in FD/MAS when administered in patients who fail to respond to bisphosphonates. Tocilizumab does not reduce bone pain in most patients, but a substantial effect in a subset cannot be ruled out in this trial powered for markers but not for pain.

Analysis of clinical features in children with McCune-Albright syndrome / 中华实用儿科临床杂志

Objective:To summarize and analyze the clinical features of McCune-Albright syndrome (MAS) in 26 children, to improve the understanding of MAS diagnosis and treatment, and to achieve early clinical diagnosis of MAS.Methods:The clinical data of 26 children with MAS treated in Department of Pediatrics, Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from August 2011 to June 2021 were retrospectively analyzed.Their clinical characteristics were summarized and studied. t-test, Mann- Whitney U test, χ 2 test or Fisher′ s exact probability method was used for comparison between groups. Results:(1) Among the 26 MAS patients enrolled, there were 22 females and 4 males.The average onset age of female and male patients was (5.87±2.94) years old and (7.48±3.36) years old, respectively.(2) In female patients, there were 7 cases with the typical triad and 15 cases with the atypical triad.(3) Female patients had the first symptom of vaginal bleeding (8/22) and breast development (14/22). Among the 4 male children, 1 case had " fracture" and 3 cases " lagged behind their peers in height" at the first visit.(4) Compared with the breast development group, the vaginal bleeding group had an earlier onset age[(4.06±1.88) years old vs.(7.82±1.82) years old] ( t=5.023, P<0.001), earlier bone maturation[(1.26±0.07) vs.(1.09±0.13)] ( t=2.933, P<0.05), a greatly lowered predicted adult height[(-2.16±0.98) SDS vs.(-0.96±1.09) SDS]( t=1.352, P<0.05), a lower blood phosphorus level[(1.41±0.14) nmol/L vs.(1.67±0.24) nmol/L] ( t=1.941, P<0.05), and a significantly elevated alkaline phosphatase level[339(313, 656) U/L vs.243(205, 452) U/L] ( U=1.000, P<0.05). All patients (8 cases) in the vaginal bleeding group had fibrous dysplasia of bone.(5) Ten patients progressed to central precocious puberty (CPP). They showed an older average age of onset[(7.27±2.69)years old vs.(4.69±2.68)years old] ( U=44.000, P<0.05), significantly earlier bone maturation at diagnosis[(1.23±0.11) vs.(1.01±0.13)] ( t=1.834, P<0.05), and a lower predicted adult height[(152.00±4.62) cm vs.(162.10±6.91) cm] ( t=3.805, P<0.05), compared with those who did not progress to CPP.(6) Eleven children developed polyostotic fibrous dysplasia of bone, and most common type (8 cases) was polyostotic fibrous dysplasia of bone, primarily at lower limb bones and skulls.(7) Of the 26 children, 20 cases had scattered Café au lait pigments on the skin.The Café au lait pigmented skin lesions in 35% (7/20) cases crossed the midline. Conclusions:With complicated clinical manifestations, MAS is more common and occurs earlier in girls than boys.It is difficult to clinically diagnose MAS in boys due to the insidious onset and atypical symptoms.Female MAS patients with vaginal bleeding as the first symptom usually have an early age of onset, advanced bone age and lower predicted adult height, so they should be monitored and evaluated clinically.Vaginal bleeding is significantly associated with polyostotic fiber dysplasia of bone in MAS patients.Therefore, it is recommended that patients with vaginal bleeding should undergo a routine bone single-photon emission computed tomography scan.This helps understand the situation of occult fiber dysplasia of bone.Patients with later diagnosis and advanced bone age should be aware of the possibility of progression to CPP.

Epidemiological and Clinical Characteristics of Fibrous Dysplasia of Bone / 肿瘤防治研究

Objective To describe the epidemiological and clinical characteristics of fibrous dysplasia of bone admitted to a single center in the past 30 years. Methods We analyzed the clinical features of 744 patients with bone fibrous dysplasia diagnosed by pathology, including age, gender, disease location, monostotic or polyostotic lesions, pathological fracture and malignant transformation. Results There were 1183 lesions in 744 patients. The mean age at admission was 31.1±13.5 years old. The ratio of male to female was close to 1:1. The most common site was the lower extremities (916(77.4%)), followed by the upper extremities (106(9.0%)). The most common sites of lower extremities were the femur (645(54.5%)) and the tibia (224(18.9%)). Polyostotic cases accounted for 25.4%, and monostotic cases accounted for 74.6%. Pathological fracture occurred in 163 (13.8%) patients. There were 6 (0.8%) patients with malignant transformation. The mean age was 40.5 years old. The mean time of malignant transformation was 7.7 years. Conclusion Fibrous dysplasia of bone is a rare group of benign bone tumors, with typical epidemiological and clinical features.

Is periostin useful as a biomarker for fibrous dysplasia? / ¿Es útil periostina como biomarcador de displasia fibrosa?

Fibrous dysplasia (FD) is an infrequent non-hereditary bone disease caused by a somatic mutation of the GNAS gene. Periostin is a novel marker that increases during tissue healing and fibrous or inflammatory diseases. We conducted an exploratory case-control study to evaluate sensitivity of periostin as a biomarker of FD. The study comprised 15 patients with FD, and healthy age- and sex-matched subjects (controls). Serum periostin levels were assessed and comparisons were established between FD patients and controls, and between patients with the monostotic and the polyostotic form of FD. No statistically significant differences in serum periostin levels were observed between the cohort of FD patients studied here and the control group (FD: 51.1±10ng/ml vs. control: 44.2±15ng/ml; p=0.15), or between the clinical forms of FD (polyostotic: 51.8±9.1ng/ml vs. monostotic: 49.6±13 ng/ml; p=0.66). A sub-analysis performed to compare serum levels of periostin in FD patients with and without a history of fractures showed no statistically significant differences [fracture patients (n=4): 41.2±17ng/ml vs. non-fracture patients (n=11): 49.9±11 ng/ml; p=0.47].Lastly, sensitivity of periostin as a biomarker of FD was analyzed, and was found to have low sensitivity to estimate disease activity [ROC curve; cut-off points: 39.625(0.867-0.467)]. To conclude, in the cohort of FD patients studied here, periostin serum levels did not differ significantly from those of the control group or between the two forms of the disease, and showed low sensitivity as a biomarker of the disease. (AU)

La displasia fibrosa (DF) es una enfermedad infrecuente del hueso, no hereditaria producida por una mutación somática del gen GNAS. Periostina (Postn) es un novedoso marcador, cuyos niveles séricos se encuentran elevados en los procesos de reparación tisular, enfermedades fibrosas o inflamatorias. Llevamos a cabo un estudio exploratorio caso-control para evaluar la sensibilidad de Postn como biomarcador de DF. Se incluyeron en el estudio 15 pacientes con DF apareados por edad y género con sujetos sanos (controles) en los cuales se evaluó los niveles séricos de Postn en pacientes con DF y controles y según forma de presentación clínica. No observamos diferencias estadísticamente significativas en los niveles séricos de Postn y el grupo control (DF: 51.1±10ng/ml vs. control: 44.2±15ng/ml; p=0.15) como así tampoco por forma clínica de DF (poliostótica: 51.8±9.1ng/ml vs. monos-tótica: 49.6±13 ng/ml; p=0.66). Posteriormente realizamos un sub-análisis para evaluar los niveles séricos de Postn en los pacientes con DF y antecedentes de fracturas no observan-do diferencias estadísticamente significativas [fracturados (n=4): 41.2±17ng/ml vs. no frac-turados (n=11): 49.9±11 ng/ml; p=0.47]. Por último analizamos la sensibilidad Postn como biomarcador de DF, mostrando este poseer escasa sensibilidad para estimar actividad de la enfermedad [curva ROC; puntos de corte: 39.625 (0.867-0.467)]. En conclusión, los ni-veles séricos de Postn en nuestra cohorte de pacientes con DF no mostraron diferencias estadísticamente significativas comparadas con el grupo control o por forma clínica de presentación, mostrando una baja sensibilidad como biomarcador de enfermedad. (AU)

Clinicopathological analysis of 105 patients with fibrous dysplasia of cranio-maxillofacial region / 北京大学学报(医学版)

OBJECTIVE@#To compare the clinicopathologic features and prognosis of the different types of fibrous dysplasia (FD) of cranio-maxillofacial region, so as to provide a new reference for clinicians to treat these patients and make prognostic judgement.@*METHODS@#Clinical records, radiographic data and pathological information of 105 patients diagnosed with FD or McCune-Albright syndrome (MAS) at the Department of Oral Pathology, Peking University Hospital of Stomatology from January 2013 to December 2020 were collected. The patients were divided into 4 groups: monostotic FDs, polyostotic FDs, MAS and a specific type called craniofacial fibrous dysplasia (CFD) limited in the craniofacial region. The clinicopathological characteristics, treatment and follow-up data of each type were analyzed.@*RESULTS@#Of all the 105 patients, 46 were males and 59 were females, with a male-to-female ratio of 1 ∶1.3. The onset age ranged from 0 to 56 years and the median age was 12 years. On the basis of different involvement conditions, 4 types were divided. The most common type was monostotic FDs (43 cases, 40.95%), including maxilla (29 cases), mandibular (12 cases) and zygoma (2 cases). 32 cases (30.48%) were diagnosed with polyostotic FDs, 7 cases (6.67%) were MAS, and 23 cases (21.90%) were CFDs confirmed by computed tomography (CT) analysis. CFD was clearly distinct from other types of FD, such as the patient gender and the serum alkaline phosphatase level in peripheral blood before operative surgery. The pathologic findings of various types FD were quite similar, whilst the predominant fibrous tissue hyperplasia could be observed in polyostotic FDs and MAS types.@*CONCLUSION@#The clinicopathologic features of FD in the cranio-maxillofacial region are different from the FD lesions in other parts of the body. The clinicopathological features of CFD are significantly different from those of monostotic and polyostotic FDs in the cranio-maxillofacial region. Therefore, the clinicians should pay attention to distinguish CFD in clinic, imaging and pathology aspects, so as to further clarify its features in clinic management and prognosis.

McCune-Albright syndrome, a rare form of precocious puberty: Diagnosis, treatment, and follow-up. / Síndrome de McCune-Albright, una forma poco frecuente de pubertad precoz: diagnóstico, tratamiento y evolución.

INTRODUCTION: McCune-Albright syndrome (MAS) is a genetic disorder defined by fibrous dysplasia of bone, café-au-lait skin spots, and autonomous hyperfunction of one or more endocrine organs. MAS is caused by activating mutations of the GNAS1 gene. The most frequent type of endocrinopathy is gonadal endocrinopathy in the form of peripheral precocious puberty. OBJECTIVE: To describe the clinical characteristics, laboratory and imaging tests at the time of diagnosis and over the course of the disease, focusing on the classical triad of MAS. POPULATION AND METHODS: Observational, descriptive, retrospective clinical study of patients with MAS seen at the Department of Endocrinology of Hospital de Niños Ricardo Gutiérrez between 1974 and 2019. RESULTS: Twelve girls are described, all of whom developed peripheral precocious puberty (PPP) secondary to functional ovarian cysts. Their age at presentation was early (2.6 ± 1.3 years). Gonadotropin levels were suppressed or in the prepubertal range with generally high estradiol levels. Ten girls had café-au-lait skin spots since birth. During the course of disease, polyostotic fibrous dysplasia was detected in all patients. The treatments used to reduce ovarian cyst recurrence and hyperestrogenism effects showed varied effectiveness. CONCLUSIONS: In this series, the onset of PPP helped to make an early diagnosis of MAS and was difficult to treat. The course of disease showed persistent gonadal hyperfunction and worsening of bone injuries.

Introducción. El síndrome de McCune-Albright (SMA) es un trastorno genético caracterizado por displasia ósea fibrosa, manchas cutáneas color "café con leche" e hiperfunción autónoma de uno o varios órganos endocrinos. El SMA es producido por mutaciones activadoras del gen GNAS1. La endocrinopatía más frecuente es la gonadal, que se manifiesta como pubertad precoz periférica. Objetivo. Describir las características clínicas y los estudios de laboratorio e imágenes en el momento del diagnóstico y a lo largo de la evolución de la enfermedad, con énfasis en la tríada clásica del síndrome. Población y métodos. Estudio clínico observacional, descriptivo, retrospectivo de las historias clínicas de pacientes con SMA de la División de Endocrinología del Hospital de Niños Ricardo Gutiérrez desde 1974 hasta 2019. Resultados. Se presentan 12 niñas. Todas tuvieron pubertad precoz periférica (PPP) secundaria a quistes ováricos funcionantes. La edad de presentación fue temprana (2,6 ± 1,3 años). Los niveles de gonadotrofinas estuvieron suprimidos o en rango prepuberal con niveles de estradiol generalmente elevados. Diez niñas tuvieron manchas "café con leche" desde el nacimiento. Durante la evolución se detectó displasia fibrosa poliostótica en todas las pacientes. Los tratamientos utilizados para disminuir la recurrencia de los quistes ováricos y los efectos del hiperestrogenismo mostraron diferente eficacia. Conclusiones. En esta serie, la aparición de PPP contribuyó al diagnóstico temprano del SMA y fue de difícil tratamiento. En la evolución persistió la hiperfunción gonadal y empeoraron las lesiones óseas.

Maternal GNAS Contributes to the Extra-Large G Protein α-Subunit (XLαs) Expression in a Cell Type-Specific Manner.

GNAS encodes the stimulatory G protein alpha-subunit (Gsα) and its large variant XLαs. Studies have suggested that XLαs is expressed exclusively paternally. Thus, XLαs deficiency is considered to be responsible for certain findings in patients with paternal GNAS mutations, such as pseudo-pseudohypoparathyroidism, and the phenotypes associated with maternal uniparental disomy of chromosome 20, which comprises GNAS. However, a study of bone marrow stromal cells (BMSC) suggested that XLαs could be biallelically expressed. Aberrant BMSC differentiation due to constitutively activating GNAS mutations affecting both Gsα and XLαs is the underlying pathology in fibrous dysplasia of bone. To investigate allelic XLαs expression, we employed next-generation sequencing and a polymorphism common to XLαs and Gsα, as well as A/B, another paternally expressed GNAS transcript. In mouse BMSCs, Gsα transcripts were 48.4 ± 0.3% paternal, while A/B was 99.8 ± 0.2% paternal. In contrast, XLαs expression varied among different samples, paternal contribution ranging from 43.0 to 99.9%. Sample-to-sample variation in paternal XLαs expression was also detected in bone (83.7-99.6%) and cerebellum (83.8 to 100%) but not in cultured calvarial osteoblasts (99.1 ± 0.1%). Osteoblastic differentiation of BMSCs shifted the paternal XLαs expression from 83.9 ± 1.5% at baseline to 97.2 ± 1.1%. In two human BMSC samples grown under osteoinductive conditions, XLαs expression was also predominantly monoallelic (91.3 or 99.6%). Thus, the maternal GNAS contributes significantly to XLαs expression in BMSCs but not osteoblasts. Altered XLαs activity may thus occur in certain cell types irrespective of the parental origin of a GNAS defect.