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200 result(s) for "Acromegaly - genetics"
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The Spectrum of GH Excess in Carney Complex and Genotype-phenotype Correlations
Carney complex (CNC) is a familial neoplasia syndrome associated with GH excess (GHE). To describe the frequency of GHE in a large cohort of patients with CNC and to identify genotype-phenotype correlations. Patients with CNC with at least 1 biochemical evaluation of GH secretion at our center from 1995 to 2021 (n = 140) were included in the study. Diagnosis of GHE was based on levels of IGF-1, GH suppression during oral glucose tolerance test, GH stimulation after thyrotropin administration and overnight GH secretion. Fifty patients (35.7%) had GHE, and 28 subjects (20%) had symptomatic acromegaly, with median age at diagnosis of 25.3 and 26.1 years, respectively. Most of the patients (99.3%) had a PRKAR1A gene defect. There was a higher risk of GHE in patients harboring a variant that led to no expression of the affected allele [hazard risk (HR): 3.06, 95% confidence interval (CI): 1.2-7.8] and for patients harboring the hotspot variant c.491_492delTG (HR: 2.10, 95% CI: 1.1-4.1). Almost half of patients with CNC had an abnormal finding on pituitary imaging. CNC patients with abnormal pituitary imaging had a higher risk of GHE (HR: 2.94, 95% CI: 1.5-5.8), especially when single or multiple adenoma-like lesions were identified. Management of patients with symptomatic acromegaly involved surgical and medical approaches. Dysregulation of GH secretion is a common finding in CNC. Knowing the clinical spectrum of this disorder and its association with genetic and imaging characteristics of the patient make more likely its prompt diagnosis and better management.
Gigantism and Acromegaly Due to Xq26 Microduplications and GPR101 Mutation
A duplicated segment of the X chromosome causes pediatric gigantism through increased levels of growth hormone. A gene in the duplicated region that encodes a G-protein–coupled receptor ( GPR101 ) seems to be the driver of the pediatric phenotype and is implicated in acromegaly. Somatic growth is orchestrated by a complex hormonal crosstalk involving the hypothalamus, pituitary, and peripheral tissues. 1 Genetic disorders that affect this network can lead to increased secretion of growth hormone, which results in acromegaly. If the excess in growth hormone occurs before epiphyseal fusion, the result can be gigantism. Nonsyndromic gigantism is most frequently caused by pituitary adenomas occurring as familial isolated pituitary adenomas or sporadically, usually as a result of mutations in the gene encoding aryl hydrocarbon receptor–interacting protein ( AIP ). 2 – 4 Other monogenic diseases can cause gigantism, but most of these conditions develop in adulthood in association . . .
E‐cadherin expression is associated with somatostatin analogue response in acromegaly
Acromegaly is a rare disease resulting from hypersecretion of growth hormone (GH) and insulin‐like growth factor 1 (IGF1) typically caused by pituitary adenomas, which is associated with increased mortality and morbidity. Somatostatin analogues (SSAs) represent the primary medical therapy for acromegaly and are currently used as first‐line treatment or as second‐line therapy after unsuccessful pituitary surgery. However, a considerable proportion of patients do not adequately respond to SSAs treatment, and therefore, there is an urgent need to identify biomarkers predictors of response to SSAs. The aim of this study was to examine E‐cadherin expression by immunohistochemistry in fifty‐five GH‐producing pituitary tumours and determine the potential association with response to SSAs as well as other clinical and histopathological features. Acromegaly patients with tumours expressing low E‐cadherin levels exhibit a worse response to SSAs. E‐cadherin levels are associated with GH‐producing tumour histological subtypes. Our results indicate that the immunohistochemical detection of E‐cadherin might be useful in categorizing acromegaly patients based on the response to SSAs.
McCune-Albright syndrome and the extraskeletal manifestations of fibrous dysplasia
Fibrous dysplasia (FD) is sometimes accompanied by extraskeletal manifestations that can include any combination of café-au-lait macules, hyperfunctioning endocrinopathies, such as gonadotropin-independent precocious puberty, hyperthyroidism, growth hormone excess, FGF23-mediated renal phosphate wasting, and/or Cushing syndrome, as well as other less common features. The combination of any of these findings, with or without FD, is known as McCune-Albright syndrome (MAS). The broad spectrum of involved tissues and the unpredictable combination of findings owe to the fact that molecular defect is due to dominant activating mutations in the widely expressed signaling protein, G s α, and the fact these mutations arises sporadically, often times early in development, prior to gastrulation, and can distribute across many or few tissues. The complexity can be mastered by a systematic screening of potentially involved tissues and cognizance that the pattern of involved tissues is established, to some degree, in utero. Thorough testing allows the clinician to establish, often times at presentation, the full extent of the disease, and importantly as well what tissues are unaffected. Treatment and follow-up can then be focused on affected systems and a meaningful prognosis can be offered to the patient and family. The authors outline screening and treatment strategies that allow for effective management of the extraskeletal manifestations of FD.
Genomic Alterations and Complex Subclonal Architecture in Sporadic GH-Secreting Pituitary Adenomas
Abstract Purpose The molecular pathogenesis of growth hormone-secreting pituitary adenomas is not fully understood. Cytogenetic alterations might serve as alternative driver events in GNAS mutation–negative somatotroph tumors. Experimental Design We performed cytogenetic profiling of pituitary adenomas obtained from 39 patients with acromegaly and four patients with sporadic gigantism by using array comparative genomic hybridization analysis. We explored intratumor DNA copy-number heterogeneity in two tumor samples by using DNA fluorescence in situ hybridization (FISH). Results Based on copy-number profiles, we found two groups of adenomas: a low–copy-number alteration (CNA) group (<12% of genomic disruption, 63% of tumors) and a high-CNA group (24% to 45% of genomic disruption, 37% of tumors). Arm-level CNAs were the most common abnormalities. GNAS mutation–positive adenomas belonged exclusively to the low-CNA group, whereas a subgroup of GNAS mutation–negative adenomas had a high degree of genomic disruption. We detected chromothripsis-related CNA profiles in two adenoma samples from an AIP mutation–positive patient with acromegaly and a patient with sporadic gigantism. RNA sequencing of these two samples identified 17 fusion transcripts, most of which resulted from chromothripsis-related chromosomal rearrangements. DNA FISH analysis of these samples demonstrated a subclonal architecture with up to six distinct cell populations in each tumor. Conclusion Somatotroph pituitary adenomas display substantial intertumor and intratumor DNA copy-number heterogeneity, as revealed by variable CNA profiles and complex subclonal architecture. The extensive cytogenetic burden in a subgroup of GNAS mutation–negative somatotroph adenomas points to an alternative tumorigenic pathway linked to genomic instability. Using cytogenetic profiling and DNA FISH analysis, we identified extensive intertumor and intratumor DNA copy-number heterogeneity reflecting a complex clonal architecture in somatotroph adenomas.
RET signalling provides tumorigenic mechanism and tissue specificity for AIP-related somatotrophinomas
It is unclear how loss-of-function germline mutations in the widely-expressed co-chaperone AIP , result in young-onset growth hormone secreting pituitary tumours. The RET receptor, uniquely co-expressed in somatotrophs with PIT1, induces apoptosis when unliganded, while RET supports cell survival when it is bound to its ligand. We demonstrate that at the plasma membrane, AIP is required to form a complex with monomeric-intracellular-RET, caspase-3 and PKCδ resulting in PIT1/CDKN2A-ARF/p53-apoptosis pathway activation. AIP-deficiency blocks RET/caspase-3/PKCδ activation preventing PIT1 accumulation and apoptosis. The presence or lack of the inhibitory effect on RET-induced apoptosis separated pathogenic AIP variants from non-pathogenic ones. We used virogenomics in neonatal rats to demonstrate the effect of mutant AIP protein on the RET apoptotic pathway in vivo. In adult male rats altered AIP induces elevated IGF-1 and gigantism, with pituitary hyperplasia through blocking the RET-apoptotic pathway. In females, pituitary hyperplasia is induced but IGF-1 rise and gigantism are blunted by puberty. Somatotroph adenomas from pituitary-specific Aip -knockout mice overexpress the RET-ligand GDNF, therefore, upregulating the survival pathway. Somatotroph adenomas from patients with or without AIP mutation abundantly express GDNF, but AIP -mutated tissues have less CDKN2A-ARF expression. Our findings explain the tissue-specific mechanism of AIP-induced somatotrophinomas and provide a previously unknown tumorigenic mechanism, opening treatment avenues for AIP -related tumours.
Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study
Non-syndromic pituitary gigantism can result from AIP mutations or the recently identified Xq26.3 microduplication causing X-linked acrogigantism (XLAG). Within Xq26.3, GPR101 is believed to be the causative gene, and the c.924G > C (p.E308D) variant in this orphan G protein-coupled receptor has been suggested to play a role in the pathogenesis of acromegaly. We studied 153 patients (58 females and 95 males) with pituitary gigantism. AIP mutation-negative cases were screened for GPR101 duplication through copy number variation droplet digital PCR and high-density aCGH. The genetic, clinical and histopathological features of XLAG patients were studied in detail. 395 peripheral blood and 193 pituitary tumor DNA samples from acromegaly patients were tested for GPR101 variants. We identified 12 patients (10 females and 2 males; 7.8 %) with XLAG. In one subject, the duplicated region only contained GPR101 , but not the other three genes found to be duplicated in the previously reported patients, defining a new smallest region of overlap of duplications. While females presented with germline mutations, the two male patients harbored the mutation in a mosaic state. Nine patients had pituitary adenomas, while three had hyperplasia. The comparison of the features of XLAG, AIP -positive and GPR101 & AIP -negative patients revealed significant differences in sex distribution, age at onset, height, prolactin co-secretion and histological features. The pathological features of XLAG-related adenomas were remarkably similar. These tumors had a sinusoidal and lobular architecture. Sparsely and densely granulated somatotrophs were admixed with lactotrophs; follicle-like structures and calcifications were commonly observed. Patients with sporadic or familial acromegaly did not have an increased prevalence of the c.924G > C (p.E308D) GPR101 variant compared to public databases. In conclusion, XLAG can result from germline or somatic duplication of GPR101 . Duplication of GPR101 alone is sufficient for the development of XLAG, implicating it as the causative gene within the Xq26.3 region. The pathological features of XLAG-associated pituitary adenomas are typical and, together with the clinical phenotype, should prompt genetic testing.
Clinicopathological Features of Growth Hormone-producing Pituitary Adenomas and Correlation With Preoperative Laboratory Findings
The histopathological variability of each type of pituitary adenoma (PA) that causes growth hormone (GH) excess influences the phenotype, radiological characteristics and therapy response of acromegaly patients. We correlated the immunohistochemical (IHC) features of GH-secreting PAs with their clinical, laboratory and imaging data. We included 32 patients with documented acromegaly; tumour specimens were histologically and IHC examined: anterior pituitary hormones, pituitary-specific transcription factor-1 (PIT-1), Ki-67 labelling index were evaluated. Macroadenomas represented 93.75%. Post-surgery disease control negatively correlated with the maximum initial tumour diameter (p=0.04). Ki-67 did not predict remission. No correlation was found between GH serum levels and IHC expression (p=0.45). PIT-1 was positive in all specimens, two had a weak expression. Four were considered PIT-1 positive plurihormonal adenomas and several had unusual IHC combinations. PIT-1 accurately classifies GH-secreting PAs. The IHC classification as well as radiological dimensions and extent influence disease control, probably being the best prognosis factors.
miR-383-5p, miR-181a-5p, and miR-181b-5p as Predictors of Response to First-Generation Somatostatin Receptor Ligands in Acromegaly
Acromegaly is a chronic systemic disease caused in the vast majority of cases by growth hormone (GH)-secreting adenoma, with surgery being the first-line treatment. When a cure is not attained with surgery, first-generation somatostatin receptor ligands (fg-SRLs) are the most common medication prescribed. Predictors of response to fg-SRLs have been studied; however, they cannot fully predict the response to fg-SRL. MicroRNAs are small RNAs, the main role of which is messenger RNA (mRNA) post-transcriptional regulation. This study aimed to identify the microRNAs involved in resistance to treatment with fg-SRLs in acromegaly. Ten patients with acromegaly undergoing treatment with fg-SRLs were selected to undergo miRNA sequencing: five controlled and five uncontrolled with treatment. Bioinformatic analysis was performed to detect differentially expressed miRNAs. Then, the same 10 samples were used for validation by qPCR and an additional 22 samples were analyzed, totaling 32 samples. e We found 59 differentially expressed miRNAs in the first analysis. miR-181a-5p and miR-181b-5p were downregulated, and miR-383-5p was upregulated in the uncontrolled group. Receiver operating characteristic (ROC) curve analysis of miR-383-5p showed an NPV of 84.3% and a PPV of 84.5%. In summary, miR-181a-5p, miR-181b-5p, and miR-383-5p are biomarkers of response to fg-SRLs, and they can be used individually or included in prediction models as tools to guide clinical decisions.
Erectile function and androgen and estrogen beta receptor gene polymorphisms in acromegalic men
Purpose Sexual dysfunctions are often experienced by male patients with acromegaly, due to a combination of hypogonadism and other comorbidities, but are a scarcely investigated complication. Erectile dysfunction is also closely related to cardiovascular diseases through endothelial dysfunction. Therefore, this project aimed to assess the prevalence of erectile dysfunction in a population of acromegalic men and evaluate its association with cardio-metabolic disorders, also exploring associations with androgen and estrogen receptor gene polymorphisms. Methods Sexually active men aged 18–65 with previous diagnosis of acromegaly were recruited. Clinical and laboratory data were retrospectively collected. Each patient also provided a blood sample for AR and ERβ gene polymorphisms analyses and filled out the IIEF-15 questionnaire. Results Twenty men with previous diagnosis of acromegaly (mean age 48.4 ± 10.0 years) were recruited. 13/20 subjects (65%) had erectile dysfunction, but only four had a concurrent biochemical hypogonadism, with no significant correlation with IIEF-15 scores. Total testosterone negatively correlated with sexual intercourse satisfaction domain ( ρ  = − 0.595; p  = 0.019) and general satisfaction domain ( ρ  = − 0.651; p  = 0.009). IGF-1 levels negatively correlated with biochemical hypogonadism ( ρ  = − 0.585; p  = 0.028). The number of CAG and CA repeats in AR and ERβ receptors genes was not significantly associated with IIEF-15 scores or with GH/IGF-1 levels, but a negative correlation between CA repeats and the presence of cardiomyopathy ( ρ  = − 0.846; p  = 0.002) was present. Conclusions Men with acromegaly have a high prevalence of erectile dysfunction, but it does not appear to be correlated with treatments, testosterone levels and AR/ER-beta signaling. Nonetheless, a shorter CA polymorphic trait (ERbeta) is associated with the presence of cardiomyopathy. If confirmed, these data may suggest an association between an incorrect hormonal balance and increased cardiovascular risk in acromegaly subjects.