Clinical implications of genetic defects in G proteins. The molecular basis of McCune-Albright syndrome and Albright hereditary osteodystrophy

Choosing the Best Tissue and Technique to Detect Mosaicism in Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS)

GNAS-activating somatic mutations give rise to Fibrous Dysplasia/McCune-Albright syndrome (FD/MAS). The low specificity of extra-skeletal signs of MAS and the mosaic status of the mutations generate some difficulties for a proper diagnosis. We studied the clinical and molecular statuses of 40 patients referred with a clinical suspicion of FD/MAS to provide some clues. GNAS was sequenced using both Sanger and Next-Generation Sequencing (NGS). We were able to identify the pathogenic variants in 25% of the patients. Most of them were identified in the affected tissue, but not in blood. Additionally, NGS demonstrated the ability to detect more patients with mosaicism (8/34) than Sanger sequencing (4/39). Even if in some cases, the clinical information was not complete, we confirmed that, as in previous works, when the patients were young children with a single manifestation, such as hyperpigmented skin macules or precocious puberty, the molecular diagnosis was usually negative. In conclusion, as FD/MAS is caused by mosaic variants, it is essential to use sensitive techniques that allow for the detection of low percentages and to choose the right tissue to study. When not possible, and due to the low positive genetic rate, patients with FD/MAS should only be genetically tested when the clinical diagnosis is really uncertain.

A Rare Skeletal Disorder, Fibrous Dysplasia: A Review of Its Pathogenesis and Therapeutic Prospects

Fibrous dysplasia (FD) is a rare, non-hereditary skeletal disorder characterized by its chronic course of non-neoplastic fibrous tissue buildup in place of healthy bone. A myriad of factors have been associated with its onset and progression. Perturbation of cell-cell signaling networks and response outputs leading to disrupted building blocks, incoherent multi-level organization, and loss of rigid structural motifs in mineralized tissues are factors that have been identified to participate in FD induction. In more recent years, novel insights into the unique biology of FD are transforming our understandings of its pathology, natural discourse of the disease, and treatment prospects. Herein, we built upon existing knowledge with recent findings to review clinical, etiologic, and histological features of FD and discussed known and potential mechanisms underlying FD manifestations. Subsequently, we ended on a note of optimism by highlighting emerging therapeutic approaches aimed at either halting or ameliorating disease progression.

Diagnosis and management of precocious sexual maturation: an updated review

The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. It is classified as central precocious puberty when premature maturation of the hypothalamic-pituitary-gonadal axis occurs, and as peripheral precocious puberty when there is excessive secretion of sex hormones, independent of gonadotropin secretion. Precocious sexual maturation is more common in girls, generally central precocious puberty of idiopathic origin. In boys, it tends to be linked to central nervous system abnormalities. Clinical evaluation should include a detailed history and physical examination, including anthropometric measurements, calculation of growth velocity, and evaluation of secondary sexual characteristics. The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. Hormonal assessment and imaging are required for diagnosis and identification of the etiology. Genetic testing should be considered if there is a family history of precocious puberty or other clinical features suggestive of a genetic syndrome. Long-acting gonadotropin-releasing hormone analogs are the standard of care for central precocious puberty management, while peripheral precocious puberty management depends on the etiology.Conclusion: The aim of this review is to address the epidemiology, etiology, clinical assessment, and management of precocious sexual maturation. What is Known: • The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. • Long-acting gonadotropin-releasing hormone agonist (GnRHa) is the standard of care for CPP management, and adequate hormone suppression results in the stabilization of pubertal progression, a decline in growth velocity, and a decrease in bone age advancement. What is New: • Most cases of precocious sexual maturation are gonadotropin-dependent and currently assumed to be idiopathic, but mutations in genes involved in pubertal development have been identified, such as MKRN3 and DLK1. • A different preparation of long-acting GnRHa is now available: 6-month subcutaneous injection.

Neonatal cholestasis can be the first symptom of McCune–Albright syndrome: A case report

BACKGROUND

McCune–Albright syndrome (MAS) is caused by postzygotic somatic mutations of the GNAS gene. It is characterized by the clinical triad of fibrous dysplasia, café-au-lait skin spots, and endocrinological dysfunction. Myriad complications in MAS, including hepatobiliary manifestations, are also reported.

CASE SUMMARY

This is a case of a 4-year-old boy who presented with MAS with neonatal cholestasis. He was suspected to have Alagille syndrome due to neonatal cholestasis with intrahepatic bile duct paucity in liver biopsy, peripheral pulmonary artery stenosis, and renal tubular dysfunction. By the age of 2 years, his cholestatic liver injury gradually improved, but he had repeated left femoral fractures. He did not exhibit endocrinological abnormality or café-au-lait skin spots. However, MAS was suspected due to fibrous dysplasia at the age of 4 years. No mutation was identified in the GNAS gene in the DNA isolated from the peripheral blood, but an activating point mutation (c.601C>T, p.Arg201Cys) was observed in the DNA extracted from the affected bone tissue and that extracted from the formalin-fixed paraffin-embedded liver tissue, which was obtained at the age of 1 mo.

CONCLUSION

MAS should be considered as a differential diagnosis for transient cholestasis in infancy.

Oral pigmented lesions in syndromic individuals: A systematic review

OBJECTIVE

To systematically integrate the available data published in the literature on oral pigmented lesions (OPL) associated with syndromes, summarizing the clinical and demographic features of the individuals.

MATERIALS AND METHODS

An electronic search was undertaken in six databases. Eligibility criteria were articles in English, Spanish, and Portuguese describing case reports or case series of OPL associated with syndromes. Data were aggregated and statistically evaluated.

RESULTS

About 108 articles reporting 149 cases of individuals with syndromes were identified. Among the affected individuals, nine syndromes were reported. The mean age at diagnosis was 35.93 years (0.41 to 83 years), with a predilection for white (n = 85/85.86%) female (n = 102/68.46%) individuals. As regards the number of lesions, 109 (73.15%) were multiple and 40 (26.85%) were single. Lip represented the anatomical location more affected (122 cases/38.01%), followed by the buccal mucosa (100 cases/31.15%). Brownish lesions accounted for 82 (69.49%) cases. The mean time of evolution was 10.52 years (0.16 to 56 years). OPL preceding diagnosis of the syndrome was observed in 111 (74.50%) cases.

CONCLUSIONS

Although these syndromes are uncommon, dentists should be able to recognize their manifestations, since oral manifestations can represent an important aspect in early diagnosis.

Frequency of GNAS R201H substitution mutation in polyostotic fibrous dysplasia: Pyrosequencing analysis in tissue samples with or without decalcification

Guanine nucleotide-binding protein/α-subunit (GNAS) mutations are involved in fibrous dysplasia (FD) pathogenesis. Here, we analyzed GNAS mutations in FD which were performed by pyrosequencing DNA isolated from formalin-fixed paraffin-embedded (FFPE) tissue. The mutation detection rate was determined in FD specimens with and without decalcification. GNAS mutation was identified in 28 cases out of 87 FDs (32.18%) [p.R201C (N = 14) and p.R201H (N = 14)]. GNAS mutation was more likely to occur in polyostotic FD (7/28, 25.0%); FD without GNAS mutation was mostly monostotic form (56/59, 94.9%, P = 0.011). The G > A (R201H) mutation was more frequent in polyostotic FD (6/14 patients, 42.9%) than the C > T (R201C) mutation (1/14, 7.1%) (P = 0.077). We divided the FD cases into two subgroups: tissue specimens that were not decalcified (N = 35, 40.2%), and tissue specimens that were decalcified (N = 52, 59.8%). GNAS mutation was more frequently identified in FD specimens that were not subjected to decalcification (23/35, 65.7%) than in FD specimens that were decalcified (5/52, 9.6%) (P = 0.001). In conclusion, mutation analysis of GNAS by pyrosequencing has diagnostic value in FFPE tissue of patients with FD, especially in specimens that were not decalcified. The R201H substitution mutation of GNAS may be involved in the pathogenesis of polyostotic FD.

Clinical characteristics and management of growth hormone excess in patients with McCune-Albright syndrome

OBJECTIVE

McCune-Albright syndrome (MAS) is a sporadic, postzygotic disease presenting with fibrous dysplasia, cafe-au-lait spots and multiple endocrinopathies. Growth hormone (GH) excess is an uncommon but potentially severe complication of MAS. This study aims to describe the clinical manifestations of GH excess in the context of MAS and analyze the responses of these patients to treatments.

DESIGN

Retrospective clinical study.

METHODS

Clinical data from 52 MAS patients were analyzed. Serum GH and IGF1 levels, as well as nadir GH levels after an oral glucose tolerance test and alkaline phosphatase (ALP) levels were determined before and after the treatment.

RESULTS

In total, 13 MAS patients (25%) had the complication of GH excess, including 10 males (76.9%). Among them, all had FD, and 6 patients had sphenoidal bone involvement. Visual deficits were present in 8 patients, and hearing deficits were present in 5. Olfactory dysfunction was observed in 3 patients. Evident pituitary adenomas were confirmed in 9 patients by MRI. These patients underwent surgery with or without pretreatment of long-acting somatostatin analogue octreotide, and 6 achieved complete remission. The serum ALP levels decreased significantly after treatment for GH excess.

CONCLUSIONS

MAS with GH excess is more common in male patients. GH excess can lead to more severe skeletal lesions in MAS patients involving more of the craniofacial bones. Complete trans-sphenoidal complete tumor excision with neuronavigational guidance is effective and could lower ALP levels. LAR is recommended as a preoperative treatment and when patients fail to achieve complete remission after surgery.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

A case of gradually manifesting McCune-Albright syndrome with a 10-year follow-up

McCune-Albright syndrome (MAS) is characterized by fibrous dysplasia (FD) of bone, café-au-lait skin pigmentation, and precocious puberty. Here we report a case of a 12-year-old girl with MAS presenting sexual precocity as initial signs, followed by FD of bone with her growth. She was referred to our hospital because of breast budding and abnormal genital bleeding at the age of 2.8 years. On physical examination, her height and weight were greater than two standard deviations of the mean ranges. Hormonal analysis revealed an elevated serum estradiol and suppressed luteinizing hormone and follicle-stimulating hormone production. Her bone age had advanced, and a 16-mm monocystic lesion was observed on her right ovary by pelvic ultrasonography. Considering the clinical and paraclinical findings, precocious pseudopuberty was suspected and periodic observations were started. Her estrogen "flare up" was transient and she had repeated similar episodes three times in the following 7 years. She complained of pain in her right hip at the age of 9.6 years, which was diagnosed as FD of bone by fluorodeoxyglucose-positron emission tomography. Although no café-au-lait skin pigmentation was observed, we made a preliminary diagnosis of MAS. Because clinical evidence for MAS can appear later in the course of recurrent autonomous cysts, careful observation and periodical assessments of patients with suspected MAS is necessary.

GNAS mutations in Pseudohypoparathyroidism type 1a and related disorders

Pseudohypoparathyroidism type 1a (PHP1a) is characterized by hypocalcaemia and hyperphosphatemia due to parathyroid hormone resistance, in association with the features of Albright's hereditary osteodystrophy (AHO). PHP1a is caused by maternally inherited inactivating mutations of Gs-alpha, which is encoded by a complex imprinted locus termed GNAS. Paternally inherited mutations can lead either to pseudopseudohypoparathyroidism (PPHP) characterized by AHO alone, or to progressive osseous heteroplasia (POH), characterized by severe heterotopic ossification. The clinical aspects and molecular genetics of PHP1a and its related disorders are reviewed together with the 343 kindreds with Gs-alpha germline mutations reported so far in the literature. These 343 (176 different) mutations are scattered throughout the 13 exons that encode Gs-alpha and consist of 44.9% frameshift, 28.0% missense, 14.0% nonsense, and 9.0% splice-site mutations, 3.2% in-frame deletions or insertions, and 0.9% whole or partial gene deletions. Frameshift and other highly disruptive mutations were more frequent in the reported 37 POH kindreds than in PHP1a/PPHP kindreds (97.3% vs. 68.7%, P < 0.0001). This mutation update and respective genotype-phenotype data may be of use for diagnostic and research purposes and contribute to a better understanding of these complex disorders.

Age-related mutations associated with clonal hematopoietic expansion and malignancies

Several genetic alterations characteristic of leukemia and lymphoma have been detected in the blood of individuals without apparent hematological malignancies. The Cancer Genome Atlas (TCGA) provides a unique resource for comprehensive discovery of mutations and genes in blood that may contribute to the clonal expansion of hematopoietic stem/progenitor cells. Here, we analyzed blood-derived sequence data from 2,728 individuals from TCGA and discovered 77 blood-specific mutations in cancer-associated genes, the majority being associated with advanced age. Remarkably, 83% of these mutations were from 19 leukemia and/or lymphoma-associated genes, and nine were recurrently mutated (DNMT3A, TET2, JAK2, ASXL1, TP53, GNAS, PPM1D, BCORL1 and SF3B1). We identified 14 additional mutations in a very small fraction of blood cells, possibly representing the earliest stages of clonal expansion in hematopoietic stem cells. Comparison of these findings to mutations in hematological malignancies identified several recurrently mutated genes that may be disease initiators. Our analyses show that the blood cells of more than 2% of individuals (5-6% of people older than 70 years) contain mutations that may represent premalignant events that cause clonal hematopoietic expansion.

Acromegaly and McCune-Albright syndrome

BACKGROUND

McCune-Albright syndrome (MAS) includes the triad of poly/monostotic fibrous dysplasia, café-au-lait spots, and hyperfunctioning endocrinopathies. Acromegaly affects around 20% of MAS patients.

AIMS

The objective was to review all reported cases of acromegaly associated with MAS.

METHODS

All studies and case reports of acromegaly in patients with MAS were systematically sought in the world literature up to January 2013. We also included new data (from three unreported cases) and updated data on 23 previously reported patients from our two centers.

RESULTS

We reviewed the cases of 112 patients (65 males). Mean age at diagnosis of acromegaly was 24.4 years (range, 3-64). Among the 40 pediatric patients, 23 (57%) had precocious puberty. GH/IGF-1 excess was suggested by accelerated growth in 85% of pediatric cases. Acromegaly was almost always associated with skull base fibrous dysplasia. Modern imaging techniques (computed tomography or magnetic resonance imaging) revealed an adenoma in 54% of the patients (macroadenoma in more than two-thirds). Median GH levels and mean IGF-1 SD score at diagnosis were 57 μg/L (2.8 to 291 μg/L) and 8 (2.3 to 24), respectively. Hyperprolactinemia was present in 81% (mean, 149 μg/L; range, 21-600). Pituitary surgery, performed in 25 cases, very rarely cured the GH/IGF-1 excess. Somatostatin analogs improved GH/IGF-1 levels in most patients but achieved control of acromegaly in only 17 (30%) of 56 patients. Pegvisomant achieved normal IGF-1 levels in 10 of 13 cases.

CONCLUSION

Acromegaly, which is present in 20-30% of patients with MAS, raises particular diagnostic and therapeutic issues.

Adenomatous multinodular goiter causing airway obstruction in an infant

Nontoxic adenomatous multinodular goiter (AMNG) in infants is a rare condition. We discuss an extremely rare case of a nontoxic AMNG in a 3-month-old female presenting with airway obstruction. Surgical resection of the mass was performed to reduce the burden on the airway and for diagnosis. The literature is reviewed, and the clinical characteristics, pathology, and surgical treatment are discussed.

Rheumatic manifestations of endocrine disease

PURPOSE OF REVIEW

Musculoskeletal complaints are a feature of several endocrine diseases. This review will update clinicians on their association, presentation, and treatment.

RECENT FINDINGS

To update clinicians on the recent literature as it is related to pathophysiology, genetic, and clinical findings on the association of these diseases and musculoskeletal complaints.

SUMMARY

Rheumatologists in the clinic are faced with different presentations of various musculoskeletal complaints every day. Every new patient encounter requires the differential diagnosis of these complaints. The first task is usually to decide with what disease in internal medicine these complaints are associated. The endocrinopathies are a group of illnesses that either present initially or exhibit sometime during the course of the disease as a variety of musculoskeletal complaints. Rheumatic manifestations may often be the initial presentation of an endocrine disorder. Each endocrine disorder may also have its own arthritic complaints, which can present as a definitive rheumatic disease such as calcium pyrophosphate dihydrate deposition disease or as a rheumatic symptom such as diffuse arthralgia. The rheumatologist as well as the primary care physician should be knowledgeable about the ways in which muscles, tendons, ligaments, and joints are affected by diseases of the endocrine system.

First report of bilateral pheochromocytoma in the clinical spectrum of HIF2A-related polycythemia-paraganglioma syndrome

CONTEXT

Molecular genetic research has so far resulted in the identification of 10 well-characterized susceptibility genes for hereditary pheochromocytoma (PHEO) or paraganglioma (PGL). Recently, a new syndrome characterized by multiple PGLs and somatostatinomas associated with congenital polycythemia due to somatic mutations in HIF2A has been reported.

OBJECTIVE

The aim of the study was to define the genetic defect in a new case of bilateral PHEO and multiple PGLs associated with congenital polycythemia.

PATIENT

A female patient presented with neonatal polycythemia (treated by phlebotomies, 1 session approximately every 4 mo), mildly enlarged cerebral ventricles, and bilateral PHEO and multiple PGLs. There was no family history of any neuroendocrine tumor or polycythemia. Surgical removal of the tumors only temporarily normalized plasma erythropoietin (Epo) levels and discontinued phlebotomies. No germline mutations were initially detected in the SDHB, SDHC, SDHD, VHL, and PHD2 genes, known to be associated with polycythemia. The PHEOs presented with a typical noradrenergic biochemical phenotype.

RESULTS

A heterozygous missense mutation (c.1589C>T) was identified in exon 12 of HIF2A, resulting in an alanine 530 substitution in the HIF-2α protein with valine (A530V). This somatic mutation was detected in the tissue from 1 PHEO and 1 PGL, with no HIF2A germline mutation found. This mutation led to stabilization of HIF-2α and hence a gain-of-function phenotype, as in previously published studies.

CONCLUSION

This case represents the first association of a somatic HIF2A gain-of-function mutation with PHEO and congenital polycythemia, and it alerts physicians to perform proper genetic screening in patients presenting with multiple norepinephrine-producing PHEOs and polycythemia. This report also extends the previous findings of a new syndrome of only multiple PGLs, somatostatinomas, and polycythemia to multiple PHEOs.

Fetal ovarian cysts: an early manifestation of McCune-Albright syndrome?

OBJECTIVE

Beyond the classic triad of peripheral precocious puberty, café-au-lait skin pigmentation and polyostotic fibrous dysplasia, partial presentation McCune-Albright syndrome (MAS) has been reported, including the association of isolated recurrent ovarian cysts in early infancy. The aims of this study were to determine whether isolated voluminous fetal unilateral ovarian cysts (diameter > 4 cm) may be associated with a Gsα activating mutation, suggestive of MAS.

DESIGN

We followed five female fetuses presenting with voluminous unilateral ovarian cysts by ultrasonography until delivery. At birth, all patients underwent percutaneous cyst aspiration and two patients later underwent ovariectomy. A sensitive PCR-based method was used to analyze the Gsα activating mutation in DNA obtained from ovarian cystic fluids or tissue.

RESULTS

Among the five cases, one Gsα mutation (R201C) was identified in the ovarian tissue.

CONCLUSIONS

We demonstrate for the first time that voluminous fetal unilateral ovarian cysts may be suggestive of MAS. Systematic search for the Gsα mutation should be performed in all newborns with voluminous fetal unilateral ovarian cysts requiring percutaneous cyst aspiration, because early diagnosis of MAS prevents unnecessary oophorectomy to eliminate questions of malignancy and imposes long-term clinical, biological, and imaging follow-up to detect other early manifestations of MAS.

mTOR links incretin signaling to HIF induction in pancreatic beta cells

Under feeding conditions, the incretin hormone GLP-1 promotes pancreatic islet viability by triggering the cAMP pathway in beta cells. Increases in PKA activity stimulate the phosphorylation of CREB, which in turn enhances beta cell survival by upregulating IRS2 expression. Although sustained GLP-1 action appears important for its salutary effects on islet function, the transient nature of CREB activation has pointed to the involvement of additional nuclear factors in this process. Following the acute induction of CREB-regulated genes, cAMP triggers a second delayed phase of gene expression that proceeds via the HIF transcription factor. Increases in cAMP promote the accumulation of HIF1α in beta cells by activating the mTOR pathway. As exposure to rapamycin disrupts GLP-1 effects on beta cell viability, these results demonstrate how a pathway associated with tumor growth also mediates salutary effects of an incretin hormone on pancreatic islet function.

Macroorchidism in an Indian boy with McCune-Albright syndrome

McCune-Albright syndrome (MAS) is defined by the clinical triad of fibrous dysplasia of bone (FD), café-au-lait spots and precocious puberty (PP). It is a rare disease with estimated prevalence between 1/100,000 and 1/1,000,000. The authors report a case of MAS in an Indian boy who had history of unilateral macroorchidism (but no other signs of MAS) since birth, then presented with PP, FD and café-au-lait spots at 6 years of age. On examination he had asymmetry of the face, café-au-lait spots and signs of sexual precocity with a right testicular volume of 25 ml (left 8 ml). Investigations revealed suppressed gonadotropins with elevated testosterone levels. Skeletal survey showed dysplastic changes involving multiple bones and advanced bone age. Reports of MAS in a boy with unilateral macroorchidism are scarce. Thus, unilateral macroorchidism at birth in a baby may be a feature of MAS and should be followed up with care.

Constitutive Gs activation using a single-construct tetracycline-inducible expression system in embryonic stem cells and mice

INTRODUCTION

The controlled expression of many genes, including G-protein coupled receptors (GPCRs), is important for delineating gene functions in complex model systems. Binary systems for inducible regulation of transgene expression are widely used in mice. One system is the tTA/TRE expression system, composed of a tetracycline-dependent DNA binding factor and a separate tetracycline operon. However, the requirement for two separate transgenes (one for each tTA or TRE component) makes this system less amenable to models requiring directed cell targeting, increases the risk of multiple transgene integration sites, and requires extensive screening for appropriately-functioning clones.

METHODS

We developed a single, polycistronic tetracycline-inducible expression platform to control the expression of multiple cistrons in mammalian cells. This platform has three basic constructs: regulator, responder, and destination vectors. The modular platform is compatible with both the TetOff (tTA) and TetOn (rtTA) systems. The modular Gateway recombineering-compatible components facilitate rapidly generating vectors to genetically modify mammalian cells. We apply this system to use the elongation factor 1α (EF1α) promoter to drive doxycycline-regulated expression of both the fluorescent marker mCherry and an engineered Gs-coupled GPCR "Rs1" separated by a 2A ribosomal skip site.

RESULTS

We show that our combined expression construct drives expression of both the mCherry and Rs1 transgenes in a doxycycline-dependent manner. We successfully target the expression construct into the Rosa26 locus of mouse embryonic stem (ES) cells. Rs1 expression in mouse ES cells increases cAMP accumulation via both basal and ligand-induced Gs mechanisms and is associated with increased embryoid body size. Heterozygous mice carrying the Rs1 expression construct showed normal growth and weight, and developed small increases in bone formation that could be observed in the calvaria.

CONCLUSIONS

Our results demonstrate the feasibility of a single-vector strategy that combines both the tTA and TRE tetracycline-regulated components for use in cells and mouse models. Although the EF1α promoter is useful for driving expression in pluripotent cells, a single copy of the EF1α promoter did not drive high levels of mCherry and Rs1 expression in the differentiated tissues of adult mice. These findings indicate that promoter selection is an important factor when developing transgene expression models.

A case of McCune-Albright syndrome associated with pituitary GH adenoma: therapeutic process and autopsy

BACKGROUND

McCune-Albright syndrome (MAS) is a clinical syndrome with low incidence, and its concurrence with pituitary GH adenoma is rare. Little of the history, treatment and outcome has been studied.

METHOD

Follow-up of a 37-year-old male patient of MAS associated with pituitary GH adenoma was performed continuously recording the disease development and the treatment process until death, after which an autopsy was performed.

RESULTS

Radiation therapy (RT) efficaciously controlled GH hypersecretion, however, it may have been the cause of the malignant transformation of the dysplastic bone tissue, which eventually caused brain hernia and death; autopsy demonstrated that the cranium had significant thickening (as much as 10 cm), the pathological diagnosis was fibrous dysplasia of bone associated with chondrosarcoma; and undifferentiated chondrosarcoma with malignant fibrous histocytoma subtype in the sellar region; nodular goiter with the thyroid gland, one nodus was pathologically demonstrated as papillary carcinoma.

CONCLUSION

GH adenoma, present in a patient with MAS, might be cured by RT; but the risk of malignant transformation of the dysplastic bone tissue in the field of irradiation make it controversial. Lessons from the case reported here told us that we should take great caution when recommending RT for patients like this.

The diagnostic and clinical significance of café-au-lait macules

Café-au-lait, also referred to as café-au-lait spots or café-au-lait macules, present as well-circumscribed, evenly pigmented macules and patches that range in size from 1 to 2 mm to greater than 20 cm in greatest diameter. Café-au-lait are common in children. Although most café-au-lait present as 1 or 2 spots in an otherwise healthy child, the presence of multiple café-au-lait, large segmental café-au-lait, associated facial dysmorphism, other cutaneous anomalies, or unusual findings on physical examination should suggest the possibility of an associated syndrome. While neurofibromatosis type 1 is the most common syndrome seen in children with multiple café-au-lait, other syndromes associated with one or more café-au-lait include McCune-Albright syndrome, Legius syndrome, Noonan syndrome and other neuro-cardio-facialcutaneous syndromes, ring chromosome syndromes, and constitutional mismatch repair deficiency syndrome.

Genetics of bone diseases: Paget's disease, fibrous dysplasia, osteopetrosis, and osteogenesis imperfecta

Over the last few years, research into the genetics of bone diseases has produced new insights into the pathophysiology of bone remodeling. The identification of SQSTM1 mutations in Paget's disease of bone established that osteoclast activation involved both binding to ubiquitin and the proteasome pathway. However, murine models fail to replicate the full phenotype, and somatic SQSTM1 mutations have been identified, suggesting a role for complex mechanisms. In patients with fibrous dysplasia of bone, postzygotic somatic mutations in the GNAS gene are now well documented. Technological advances have improved the detection of somatic mutations in peripheral blood cells. Osteopetrosis is characterized by increased bone density due to deficient osteoclastic bone resorption. Most of the genes involved in the various clinical patterns of osteopetrosis have been identified. The identification of LRP5 gain-of-function mutations in autosomal dominant osteopetrosis type I prompted a revision of the classification scheme, and this form is now being included among the high-bone-mass diseases. Osteogenesis imperfecta is characterized by an inherited abnormality in bone formation that manifests as osteopenia with increased bone fragility. Mutations in the COL1A1 and COL1A2 genes are found in over 90% of patients. The recent identification of mutations in the CRTAP, LEPRE1, and PPIB genes in recessive forms has radically changed the classification of osteogenesis imperfecta and generated new pathophysiological hypotheses.

Another unusual presentation of McCune Albright syndrome with fibrous dysplasia, unilateral testicular enlargement, and testicular microlithiasis

We report on a 9-year-old boy with atypical McCune Albright syndrome who presented with polyostotic fibrous dysplasia, unilateral testicular enlargement without signs of sexual precocity, and bilateral testicular microlithiasis on sonography. This is the first report of a patient with an atypical form of MAS presenting with unilateral testicular enlargement not associated with sexual precocity, and with testicular microlithiasis.

Cushing syndrome in the McCune-Albright syndrome

CONTEXT

Cushing syndrome (CS) is a rare but potentially fatal feature of McCune-Albright syndrome (MAS). Optimal management, prognostic features, and long-term follow-up of this disorder have not been described.

SETTING

The study was conducted at an academic tertiary care center.

PATIENTS

A total of 112 patients participating in a natural history study at the National Institutes of Health (NIH) were evaluated, and 21 published cases were reviewed.

INTERVENTIONS

Subjects received observation, medical management, or bilateral adrenalectomy.

MAIN OUTCOME MEASURES

We measured prevalence, prognostic factors, and natural history.

RESULTS

The prevalence of CS among NIH patients was 7.1%. The median age at diagnosis was 3 months. Clinical features included "Cushingoid facies" (66.7%), failure to thrive (60.0%), low birth weight (50.0%), liver disease (36.7%), and heart disease (26.7%). Six patients (20.0%) died, four after adrenalectomy. Death was more likely in patients with comorbid heart disease (odds ratio, 13.3; P < 0.05). Of 23 survivors, 13 underwent adrenalectomy, and 10 exhibited spontaneous resolution. Two patients with spontaneous resolution who were tested later in life (3 and 15 yr after resolution) continued to have low-level, autonomous adrenal function with biochemical adrenal insufficiency. Compared to MAS patients without CS, patients with CS were more likely to have a cognitive/developmental disorder (44.4 vs. 4.8%; P < 0.001; odds ratio, 8.8).

CONCLUSIONS

Comorbid heart and liver disease were poor prognostic markers and may indicate the need for prompt adrenalectomy. The high incidence of cognitive disorders indicates a need for close developmental follow-up and parental counseling. Patients with spontaneous resolution of CS may develop adrenal insufficiency, and they require long-term monitoring.

Rheumatic manifestations of endocrine diseases

PURPOSE OF REVIEW

Musculoskeletal complaints accompanying or as a result of endocrine disorders are common and have been well described. This review re-examines these associations in light of newer information on biology and genetics.

RECENT FINDINGS

In this article, we describe the recent studies on pathophysiology of the muscular skeletal complaints in endocrine disease. In addition we report on population as well as genetic studies, which address the relationship between endocrine and rheumatologic disease, both of which are autoimmune.

SUMMARY

Very often, the presentation of rheumatic manifestations is the initial presentation of endocrine disease. Being aware of the presentation as well as the unique physiology of these complaints will help alert the clinician to an early diagnosis of endocrine disease. In addition understanding whether certain endocrine disease occurs more often in rheumatologic illness will enable the clinician to investigate their occurrence early, leading to earlier intervention and resulting in decreased morbidity from these concomitant illnesses.

Regulation of spermatogenesis in McCune-Albright syndrome: lessons from a 15-year follow-up

CONTEXT

McCune-Albright syndrome (MAS) is a disorder caused by a post-zygotic gain-of-function mutation in the gene encoding the Gs-alpha protein. Sexual precocity, common in girls, has been reported in only 15% of boys, and little is known on the long-term evolution of MAS in males.

OBJECTIVE

In a boy with MAS, we studied spermatogenesis, testis histology, and immunohistochemistry with the aim to shed light on seminiferous tubule activity.

DESIGN

A boy who presented at the age of 2.9 years with sexual precocity, monolateral macroorchidism, increased testosterone levels, and suppressed gonadotropins was followed up until the age of 18.

RESULTS

Throughout follow-up testicular asymmetry persisted and gonadotropin and testosterone pattern did not change. At the age of 18, inhibin B was undetectable while alpha-immunoreactive inhibin was within normal range. Anti-Mullerian hormone level was slightly subnormal. Sperm cells were 3,900,000 per ejaculate. Histology of both testes showed spermatogonia, spermatocytes, and, in some tubes, matured spermatozoa. Sertoli cells were markedly stained with anti-inhibin alpha-subunit antibody in both the testes. There was no immunostaining of Sertoli, Leydig, or germ cells with anti-betaA or anti-betaB antibody. MAS R201H mutation was identified in both the testes.

CONCLUSION

The 15-year follow-up in this boy with MAS demonstrated that autonomous testicular activation and gonadotropin suppression persisted over time. This provides an interesting model of active spermatogenesis despite long-term FSH suppression. It also suggests that FSH is needed for the full expression of the inhibin betaB-subunit gene, an expression previously reported in the germ and Leydig cells of normal adult subjects.

The role of type 1 and type 2 5'-deiodinase in the pathophysiology of the 3,5,3'-triiodothyronine toxicosis of McCune-Albright syndrome

CONTEXT

McCune-Albright syndrome (MAS) is caused by mutations in GNAS (most often R201C or R201H) leading to constitutive cAMP signaling and multiple endocrine dysfunctions, including morphological and functional thyroid involvement.

OBJECTIVE

The objective of the study was to characterize the clinical and molecular features of the MAS-associated thyroid disease in a large cohort of patients.

DESIGN

This was a retrospective analysis.

SETTING

The study was conducted at the National Institutes of Health Clinical Center.

PATIENTS

The study included 100 consecutive MAS patients.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE

Functional and morphological evaluation of the thyroid was measured. Ex vivo experiments were performed on MAS thyroid samples to study the effects of the GNAS mutations on the 5'-deiodinases. Reconstitution experiments in HEK-293 cells were performed to study the effects of GNAS mutations on the type-2 5'-deiodinase.

RESULTS

Fifty-four patients had abnormal thyroid ultrasound findings. This group, compared with patients without abnormal findings, had higher T(3) to T(4) ratio, indicating an elevated 5'-deiodinase activity. Thyroid samples from MAS subjects, compared with normal tissue, showed a significant increase in both type 1 (D1) and type 2 (D2) 5'-deiodinase activity (D1 control 5.9 +/- 4.5 vs. MAS 41.7 +/- 26.8 fmol/min.mg, P < 0.001; D2 control 28.3 +/- 13.8 vs. MAS 153.1 +/- 43.7 fmol/min.mg, P < 0.001). Compared with cells transfected with the wild-type R201 allele, the basal transcriptional activity of the D2 promoter was significantly increased in both mutants (C and H) (R 10733 +/- 2855, vs. C 18548 +/- 4514, vs. H 19032 +/- 4410 RLU +/- SD, P < 0.001).

CONCLUSION

Thyroid pathology is a common occurrence in MAS. Consistent with the molecular etiology of the disease, the shift in T(3) to T(4) ratio is at least in part secondary to a cAMP-mediated intrathyroidal activation of D2 and to elevated D1 activity.

A pseudohypoparathyroidism type Ia patient with normocalcemia

Pseudohypoparathyroidism type Ia (PHP-Ia), one of 4 types of PHP, is a genetic disease characterized by clinical hypoparathyroidism caused by parathyroid hormone (PTH) resistance. In addition, patients with PHP-Ia show resistance to other hormones as well as Albright's hereditary osteodystrophy (AHO), a constellation of features including short stature, obesity, brachydactyly, ectopic ossifications, and/or mental retardation. Hypocalcemia is one of the hallmarks of PHP-Ia, but several PHP-Ia patients have been described to have normocalcemia. We encountered a 10-year-old girl with typical Albright's hereditary osteodystrophy with round face, short stature, brachydactyly, and obesity. Biochemical examination showed normocalcemia and increased PTH levels. Ellsworth-Howard test did not show any responses of urinary cAMP and phosphate. Based on these findings, she was diagnosed as having PHP-Ia with normocalcemia. Sequencing analysis of the GNAS gene identified a heterozygous missense mutation in exon 13 (R385H), which was previously reported in a PHP-Ia patient. The exact reason for her normocalcemia is not determined, but we must recognize heterogeneous biochemical findings even in PHP-Ia.

Cognitive impairment is prevalent in pseudohypoparathyroidism type Ia, but not in pseudopseudohypoparathyroidism: possible cerebral imprinting of Gsalpha

OBJECTIVE

Pseudohypoparathyroidism type Ia (PHP-Ia) is a hereditary disorder characterized by resistance to multiple hormones that work via cAMP such as PTH and TSH, accompanied by typical skeletal features including short stature and brachydactyly, termed Albright hereditary osteodystrophy (AHO). In affected kindreds, some members may have AHO but not hormone resistance; they are termed as pseudopseudohypoparathyroidism (PPHP). The molecular basis for the disorder is heterozygous inactivating mutation of the Gsalpha gene. In affected families, subjects with both PHP-Ia and PPHP have the same Gsalpha mutations. The skeletal features common to PPHP and PHP-Ia are presumably caused by tissue-specific Gsalpha haploinsufficiency. Other features that distinguish between PPHP and PHP-Ia, such as the multihormone resistance, are presumably caused by tissue-specific paternal imprinting of Gsalpha. This suggests that major differences in phenotype between PHP-Ia and PPHP point to specific tissues with Gsalpha imprinting. One such major difference may be cognitive function in PHP-Ia and PPHP.

DESIGN

Description of a large family with PHP-Ia and PPHP.

PATIENTS

Eleven affected subjects with PHP-Ia or PPHP in one family.

MEASUREMENTS

Cognitive impairment (CI) was defined by a history of developmental delay, learning disability and the Wechsler intelligence scale.

RESULTS

CI occurred only in the five PHP-Ia but not in the six PPHP subjects. Hypothyroidism which occurred in all PHP-Ia subjects was apparently not the cause of CI as it was mild, and was treated promptly. Analysis of additional Israeli cases, and the published cases from the literature, all with documented Gsalpha mutations, revealed that CI is prevalent in PHP-Ia [60 of 77 subjects (79%)] but not in PPHP [3 of 30 subjects (10%)] (P < 1 x 10(-6)).

CONCLUSION

We suggest that Gsalpha is imprinted in the brain.

McCune-Albright syndrome associated with acromegaly and bipolar affective disorder

McCune-Albright syndrome is a rare disorder caused by an activating mutation in the gene (GNAS1) encoding the subunit of the G protein. This syndrome is characterized by polyostotic fibrous dysplasia, café-au-lait pigmentation, and multiple endocrine hyperfunction. A 29-year-old male with polyostotic fibrous dysplasia, café-au-lait pigmentations, and pituitary adenoma is presented in this report. The patient had accompanying bipolar affective disorder, which might have been caused by the underlying genetic abnormality.

McCune-Albright syndrome and disorders due to activating mutations of GNAS1

It has been more than seven decades since Drs. Fuller Albright and Donovan McCune published the first reports on individuals with McCune-Albright syndrome (MAS). Since then, the classic triad of precocious puberty, café-aulait spots, and polyostotic bone dysplasia continues to define the syndrome. However, having gathered a better picture of the pathophysiology of MAS, the way this condition is understood has changed. Isolated activating mutations of the alpha subunit of the G protein (GNAS1) have been found in different tissues, including pituitary adenomas, thyroid adenomas, ovarian cysts, monostotic bone dysplasia, and the adrenal glands, to name a few. For this reason, we have added 'and disorders due to activating mutations of GNAS1' to the title of this review. We discuss here the clinical consequences of GNAS1 activating mutations in different body systems and organs, the diagnostic approach to MAS, and the current therapeutic recommendations.

Chronically increased Gsalpha signaling disrupts associative and spatial learning

The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to Drosophila to Aplysia. Studies of olfactory learning in Drosophila suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we provide genetic evidence of the behavioral and physiological effects of increased signaling through the cAMP/PKA pathway in mice. We have generated transgenic mice in which the expression of a constitutively active form of Gsalpha (Gsalpha* Q227L), the G protein that stimulates adenylyl cyclase activity, is driven in neurons within the forebrain by the promoter from the CaMKIIalpha gene. Despite significantly increased adenylyl cyclase activity, Gsalpha* transgenic mice exhibit PKA-dependent decreases in levels of cAMP due to a compensatory up-regulation in phosphodiesterase activity. Interestingly, Gsalpha* transgenic mice also exhibit enhanced basal synaptic transmission. Consistent with a role for the cAMP/PKA pathway in learning and memory, Gsalpha* transgenic mice show impairments in spatial learning in the Morris water maze and in contextual and cued fear conditioning tasks. The learning deficits observed in these transgenic mice suggest that associative and spatial learning requires regulated Gsalpha protein signaling, much as does olfactory learning in Drosophila.

Pegvisomant for the treatment of gsp-mediated growth hormone excess in patients with McCune-Albright syndrome

CONTEXT

GH excess affects approximately 20% of the patients with McCune-Albright syndrome (MAS). MAS is caused by sporadic, postzygotic, activating mutations in the GNAS gene, which codes for the cAMP-regulating protein, G(s)alpha (gsp oncogene). These same mutations are found in approximately one third of the sporadic cases of acromegaly.

OBJECTIVE

We examined efficacy of the GH receptor antagonist, pegvisomant, in controlling gsp oncogene-mediated GH excess and skeletal disease (fibrous dysplasia of bone) associated with MAS.

SETTING AND PATIENTS

Five MAS patients with GH excess were treated with 20 mg/d sc injection of pegvisomant for 12 wk in a randomized, double-blind, placebo-controlled crossover study at the National Institutes of Health.

MAIN OUTCOME MEASURES

The primary measure of efficacy was normalization of IGF-I. Secondary outcome measures were reduction in serum IGF binding protein-3 (IGFBP-3), improvement of fatigue and sweating, and reduction in markers of bone metabolism and bone pain.

RESULTS

Combined mean changes in serum IGF-I at 6 and 12 wk were -236.4 ng/ml (53%, P < 0.005) and -329.8 ng/ml (62%, P < 0.001), respectively. IGFBP-3 decreased by 0.8 mg/liter (24%, P < 0.01) and 2.9 mg/liter (37%, P < 0.005), respectively. There were no significant changes in signs and symptoms of acromegaly or markers of bone metabolism and bone pain, nor was there a significant change in pituitary size. Retrospective comparison of the degree of control achieved with pegvisomant vs. other medications (long-acting octreotide +/- dopamine agonist) in the same group showed that the two regimens were similarly effective.

CONCLUSIONS

Pegvisomant effectively reduced IGF-I and IGFBP-3 levels in gsp-mediated GH excess but had no effect on fibrous dysplasia.

Rare syndromes

Dermatologists may also encounter patients presenting with skin lesions that reflect an underlying endocrine disorder not commonly seen in daily practice. Some of these endocrine disorders include glucagonoma, neurofibromatosis type 1, McCune-Albright syndrome, multiple endocrine neoplasia, the Carney complex, carcinoid tumors, and mastocytosis. The clinical syndrome classically associated with glucagonoma includes necrolytic migratory erythema, weight loss, diabetes mellitus, anemia, cheilitis, venous thrombosis, and neuropsychiatric symptoms. The hallmarks of neurofibromatosis type 1 are the multiple café-au-lait spots and associated cutaneous neurofibromas. Other presenting features include freckling, peripheral neurofibromas, Lisch nodules, bone abnormalities, tumors, neurologic abnormalities and hypertension. McCune-Albright syndrome is characterized by café-au-lait spots, polyostotic fibrous dysplasia, sexual precocity, and hyperfunction of multiple endocrine glands. Multiple endocrine neoplasia type 2A is characterized by medullary thyroid cancer, pheochromocytoma, and primary parathyroid hyperplasia. In some patients with multiple endocrine neoplasia type 2A, cutaneous lichen amyloidosis may also be present. Multiple endocrine neoplasia type 2B is characterized by medullary thyroid cancer and pheochromocytoma but not hyperparathyroidism. The syndrome also includes mucosal neuromas, typically involving the lips and tongue, intestinal ganglioneuromas and a marfanoid habitus. Multiple endocrine neoplasia type 1 is an autosomal dominant predisposition to tumors of the parathyroid glands (four-gland hyperplasia), anterior pituitary, and pancreatic islet cells; hence, the mnemonic device of the "3 Ps"; multiple cutaneous lesions (angiofibromas and collagenomas) are frequent in patients with multiple endocrine neoplasia type 1. Carney complex may be viewed as a form of multiple endocrine neoplasia because affected patients often have tumors of two or more endocrine glands, including primary pigmented nodular adrenocortical disease (some with Cushing's syndrome), pituitary adenoma, testicular neoplasms, thyroid adenoma or carcinoma, and ovarian cysts. Additional unusual manifestations include psammomatous melanotic schwannoma, breast ductal adenoma, and a rare bone tumor, osteochondromyxoma. Carcinoid syndrome is the term applied to a constellation of symptoms mediated by various humoral factors elaborated by some carcinoid tumors; the major manifestations are diarrhea, flushing, bronchospasm, and cardiac valvular lesions. Mast cell diseases include all disorders of mast cell proliferation. These diseases can be limited to the skin, referred to as "cutaneous mastocytosis," or involve extracutaneous tissues, called "systemic mastocytosis." Patients present with urticaria pigmentosa, mastocytoma, or diffuse cutaneous mastocytosis. Systemic involvement may be gastronintestinal, hematologic, neurologic, and skeletal.

Low prevalence of Gs alpha mutations in śomatotroph adenomas of children and adolescents

Mutations in the gene coding for the alpha-subunit of the heterotrimeric stimulatory G protein Gs are the most frequently identified molecular events in the development of somatotroph adenomas in adults. In children and adolescents, somatotroph adenomas are rare, and only two cases with the Gs alpha mutation have been reported so far. In this study, we therefore investigated the prevalence of activating Gs alpha mutations in 17 patients younger than 20 years with pituitary growth hormone-secreting adenomas and examined the characteristics of mutation-positive cases. The most common C-->T substitution in codon 201 was detected in two children. Interestingly, in contrast to the remaining cases, the adenomas positive for the Gs alpha mutation proved to be nonsporadic, but part of a syndrome associated with endocrine tumors in both individuals. Additional tests confirmed McCune-Albright syndrome in the first patient and multiple endocrine neoplasia type 1 syndrome in the second patient. In contrast to the findings in adult cases, somatotroph adenomas in young patients seem to carry somatic Gs alpha mutations at a lower frequency, and germ-line or early postzygotic mutational events may be responsible for the shortened latency of tumorigenesis.

Clinical presentation of McCune-Albright syndrome in males

The aims of this study were: (a) to survey gender prevalence and clinical findings at diagnosis in a series of patients who manifested at the time of this study the classical triad of McCune-Albright syndrome (MAS); (b) to investigate whether clinical presentation of MAS in boys may be different from that in girls; (c) to confirm whether boys with MAS may show a peculiar picture of testicular microlithiasis (TM) by testicular ultrasonography (US). Twenty-six patients (10 boys) with the classical clinical manifestations of MAS were recruited for the present study from the database of the Italian Multicenter Study Group on MAS. Age at diagnosis of MAS was significantly lower in girls than in boys (p < 0.025). Whilst there was no difference in the prevalence of skin and bone fibrous dysplasia for the two groups, a significantly higher prevalence of peripheral precocious puberty (PPP) was found in girls (chi2 = 6.5, p < 0.025). Moreover, PPP onset was earlier in females than in males (2.8 +/- 2.3 vs. 6.9 +/- 2.7 years, p < 0.005). In one boy, aged 2.9 years, the first clinical manifestation of MAS was monolateral testicular enlargement in the context of a picture of classical PPP. US scanning of the testes, at the time of the present study, showed bilateral hyperechogeneic multiple spots, compatible with diagnosis of TM, in 6/10 boys.

CONCLUSIONS

(a) MAS is slightly more frequent in females. (b) PPP in MAS is significantly more frequent and earlier in girls. (c) PPP in boys with MAS is generally associated with bilateral testicular enlargement, but monolateral macroorchidism may also be seen. (d) TM may be another marker for MAS in males.

McCune-Albright syndrome: clinical picture and natural history in children and adolescents

The classical triad of McCune-Albright syndrome (MAS) consists of polyostotic fibrous dysplasia (FD), skin hyperpigmentation (café-au-lait spots), and endocrine dysfunction, frequently seen in females as precocious puberty. Patients with MAS display mosaicism of activating somatic mutations of the alpha-subunit of Gs. Thus, the clinical presentation of each individual is dependent on the particular distribution of affected cells, causing a broad spectrum of endocrine and non-endocrine manifestations. Typical endocrinopathies are precocious puberty, hyperthyroidism, growth hormone excess, hyperprolactemia, and hypercortisolism. The onset of these manifestations is usually during infancy and childhood. Since specific treatment is required, the prognosis depends on the severity of each individual endocrine manifestation. Additionally, there are non-endocrine manifestations, such as fibrous dysplasia of bone (FD), renal phosphate wasting, and skin hyperpigmentation, i.e. café-au-lait spots. FD, mostly polyostotic, causes fractures needing surgical and orthopedic treatment. Since previous studies have suggested the overall prognosis of patients with McCune-Albright syndrome to be non-fatal, recent data have drawn our attention to non-endocrine affections, including hepatobiliary dysfunction and cardiac disease, which are probably an important risk factor for early death. In summary, the clinical picture in MAS is related to its mosaic nature, i.e. any cell, tissue and organ in any site of the body could be affected to varying degrees, ranging from one or two mild clinical signs with excellent long-term prognosis to a severe life-threatening multiorgan disease.

McCune-Albright syndrome in a boy may present with a monolateral macroorchidism as an early and isolated clinical manifestation

BACKGROUND

Testis enlargement in McCune-Albright syndrome (MAS) is generally bilateral and associated with clinical and biochemical manifestations of sexual precocity.

CASE REPORT

We describe for the first time an unreported clinical expression of MAS in a 4.6-year-old boy presenting with monolateral testis enlargement and no signs of sexual precocity or other clinical manifestations of MAS at the time of presenting with macroorchidism. Both testosterone and LHRH-stimulated gonadotropin levels were in the prepubertal range. Serum inhibin B was increased to a pubertal level indicating Sertoli cell activation. The histological and immunocytochemical evaluation of the enlarged testis revealed Sertoli cell hyperplasia with no mature Leydig cells. Mutation R201C of GNAS1 gene, classically responsible for MAS, was identified in DNA samples from the right testis biopsy and leukocytes.

CONCLUSIONS

(a) MAS should be taken into consideration in the clinicopathological approach to a boy with monolateral macroorchidism; (b) testicular enlargement may be only the presenting clinical manifestation of MAS and is not necessarily linked to manifestations of peripheral precocious puberty; (c) testicular autonomous hyperfunction in MAS may be restricted to Sertoli cells, as also demonstrated previously by others.

Fibrous dysplasia of the clivus with a second T8 bone lesion: case report

BACKGROUND

We present a rare case of a probably poliostotic fibrous dysplasia of the clivus in a young woman with a clival and vertebral involvement. We also compare our case with data reported in tables that include all cases of clival fibrous dysplasia present in literature.

CASE DESCRIPTION

Thirty-year-old women presented with headache. We reviewed radiological and clinical literature before surgery. It was possible to perform a preoperative diagnosis of fibrous dysplasia of the clivus so it was possible to adopt a minimally invasive surgical approach on the clivus. The diagnosis of fibrous dysplasia of the clivus was confirmed after the operation. As the patient was asymptomatic, we did not operate on the vertebral lesion which was stable after 1 year.

CONCLUSION

We draw the conclusion that it is possible to obtain a correct preoperative diagnosis of fibrous dysplasia based on magnetic resonance imaging and computed tomographic scans; this makes it possible to avoid major surgical operations. The reported case is particularly interesting because apart from the clival fibrous dysplasia, a vertebral involvement of the same type can be assumed; this association has never been reported in literature.

Mosaicism in cutaneous pigmentation

PURPOSE OF REVIEW

This article reviews the disorders of patterned dyspigmentation and discusses the pathogenesis of the pigmentary changes.

RECENT FINDINGS

A range of cytogenetic abnormalities has been detected in patterned pigmentary disease. This molecular heterogeneity correlates with the wide spectrum of clinical phenotypes observed. Many of the molecular defects overlap with genes known to play a role in pigmentation. Our understanding of the underlying genetic mechanisms for these mosaic conditions is evolving with advances in technology and dissection of the molecular pathways involved in melanocyte biology.

SUMMARY

The causal heterogeneity of patterned dyspigmentation promises to reveal clues about the differentiation, function, and control of melanocytes in embryonic and postnatal development.

Molecular characterization of a cryptic 2q37 deletion in a patient with Albright hereditary osteodystrophy-like phenotype

The Albright hereditary osteodystrophy-like (AHO-like) syndrome was recently defined as a rare dysmorphic syndrome including brachymetaphalangism and mental retardation. This phenotype occurs in Albright hereditary osteodystrophy (AHO) but unlike it, the level of the Gs alpha protein activity is not reduced. To date 59 patients with these clinical and biochemical features have been reported, and for the majority of them (57/59) a cytogenetically visible 2q37 deletion has been observed. We report a new case of typical AHO-like syndrome with normal karyotype. Using the polymorphic marker D2S125 we found a loss of heterozygosity suggestive of a de novo 2q37 deletion of maternal origin. This hypothesis was confirmed by FISH analysis with a subtelomeric 2q probe containing the D2S90 marker. Genotypic analysis allowed us to map the proximal breakpoint of the subtelomeric deletion within an interval delimited by D2S2338 (present) and D2S2253 (deleted). This 2q subtelomeric deletion as small as 4 Mb is to date the smallest one observed in association with a typical AHO-like phenotype, and allows us to move the centromeric boundary of the AHO-like critical region by 750 kb towards the 2q telomere.

GSPalpha mutations in Mexican patients with acromegaly: potential impact on long term prognosis

OBJECTIVE

The frequency of activating mutations of the GSPalpha gene as the etiology of GH-secreting pituitary adenomas has been the subject of important ethnogenetic variability. Whereas up to 40% of Caucasian patients with acromegaly have tumors which harbor these somatic mutations, their prevalence among Asian populations is much lower. The correlation between the presence of these mutations and the clinical and biological behavior of these tumors has also been a matter of controversy. In the present study, we investigated the prevalence of GSPalpha mutations in GH-secreting tumors obtained from a genetically homogenous population of Mexican patients with acromegaly. We also sought to establish whether or not the presence of these mutations correlates in any way with the clinical or biochemical characteristics of the disease.

STUDY DESIGN AND METHODS

Fifty eight GH-secreting pituitary adenomas were examined for the presence of point mutations in either codon 201 or 227 of the GSPalpha gene, using PCR and direct sequencing of DNA extracted from either fresh or paraffin-embedded tissues. Patients were prospectively followed clinically and biochemically for up to nine years after pituitary surgery.

RESULTS

Heterozygous point mutations in exon 8 (codon 201) were found in 11 patients (19%), and no molecular alterations were evident in exon 9. The frequency and severity of the different clinical features of acromegaly did not differ between patients with and without GSPalpha mutations. Patients with and without mutations had pre-operative GH and IGF-I elevations of similar magnitude, and although microadenomas appeared to be more frequent among patients with GSPalpha mutations, this did not reach statistical significance. Upon short-term follow-up, biochemical cure (normal age- and gender-adjusted IGF-I and post-glucose GH below 1 ng/mL) was similarly achieved in both groups. After 3-9 years of post-operative follow up however, a significantly greater proportion of patients with the mutation achieved a "safe" basal GH value (100% vs 33%, p=0.001) as well a lower nadir post-glucose GH (0.53+/-0.5 vs 2.9+/-6.2 ng/mL, p=0.04) although the rate of IGF-1 normalization did not differ between the 2 groups.

CONCLUSIONS

Our results show that the prevalence of GSPalpha mutations in Mexican patients with acromegaly is intermediate between that found in Asian and Caucasian populations. In this well-defined genetic population the presence of codon 201 mutations appeared to be associated with a greater probability of achieving a "safe" GH value upon long-term follow-up.

A novel technique based on a PNA hybridization probe and FRET principle for quantification of mutant genotype in fibrous dysplasia/McCune-Albright syndrome

Somatic mutations are present in various proportions in numerous developmental pathologies. Somatic activating missense mutations of the GNAS gene encoding the Gs(alpha) protein have previously been shown to be the cause of fibrous dysplasia of bone (FD)/McCune-Albright syndrome (MAS). Because in MAS patients, tissues as diverse as melanocytes, gonads and bone are affected, it is generally accepted that the GNAS mutation in this disease must have occurred early in development. Interestingly, it has been shown that the development of an active FD lesion may require both normal and mutant cells. Studies of the somatic mosaic states of FD/MAS and many other somatic diseases need an accurate method to determine the ratio of mutant to normal cells in a given tissue. A new method for quantification of the mutant:normal ratio of cells using a PNA hybridization probe-based FRET technique was developed. This novel technique, with a linear sensitivity of 2.5% mutant alleles, was used to detect the percentage mutant cells in a number of tissue and cell culture samples derived from FD/MAS lesions and could easily be adapted for the quantification of mutations in a large spectrum of diseases including cancer.

Dental characteristics of fibrous dysplasia and McCune-Albright syndrome

OBJECTIVE

Fibrous dysplasia (FD) is a skeletal disorder often associated with McCune-Albright syndrome, a rare multisystem disorder caused by GNAS1 gene mutation. FD frequently affects the craniofacial bones, including the maxilla and the mandible; nevertheless, its effects on dental tissues and the implications for dental care remain unclear. The aim of this study was to characterize the dental features associated with FD and the reaction of affected bones to routine dental therapy. Study design Thirty-two patients with FD underwent dental evaluation and endocrine testing as part of the diagnosis of FD/McCune-Albright syndrome. Any dental anomalies were recorded, and the associations between endocrinopathies and dental anomalies were analyzed statistically by means of the paired t test.

RESULTS

Eighty-four percent had FD in the maxilla and/or mandible; endocrine dysfunction; and/or renal phosphate wasting. The caries index scores were 2.9 (ages 4-17 years) and 9.6 (ages 18-50 years). Malocclusion (81%) and other prevalent dental anomalies (41%) included tooth rotation, oligodontia, and taurodontism. The expansion of the maxilla or mandible by FD did not distort the dental arch curvature, and routine dental therapies such as extractions, restorations, and orthodontic treatment did not exacerbate FD lesions.

CONCLUSION

Maxillomandibular FD was associated with higher rates of caries and malocclusion than were present in healthy patients. Furthermore, patients with FD did not require special dental management and were able to undergo routine dental care without an exacerbation of FD lesions.