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Background: X-linked acrogigantism (X-LAG; MIM: 300942) is a severe form of pituitary gigantism caused by chromosome Xq26.3 duplications involving GPR101. X-LAG-associated duplications disrupt the integrity of the topologically associating domain (TAD) containing GPR101 and lead to the formation of a neo-TAD that drives pituitary GPR101 misexpression and gigantism. As X-LAG is fully penetrant and heritable, duplications involving GPR101 identified on prenatal screening studies, like amniocentesis, can pose an interpretation challenge for medical geneticists and raise important concerns for patients and families. Therefore, providing robust information on the functional genomic impact of such duplications has important research and clinical value with respect to gene regulation and triplosensitivity traits., Methods: We employed 4C/HiC-seq as a clinical tool to determine the functional impact of incidentally discovered GPR101 duplications on TAD integrity in three families. After defining duplications and breakpoints around GPR101 by clinical-grade and high-density aCGH, we constructed 4C/HiC chromatin contact maps for our study population and compared them with normal and active (X-LAG) controls., Results: We showed that duplications involving GPR101 that preserved the centromeric invariant TAD boundary did not generate a pathogenic neo-TAD and that ectopic enhancers were not adopted. This allowed us to discount presumptive/suspected X-LAG diagnoses and GPR101 misexpression, obviating the need for intensive clinical follow-up., Conclusions: This study highlights the importance of TAD boundaries and chromatin interactions in determining the functional impact of copy number variants and provides proof-of-concept for using 4C/HiC-seq as a clinical tool to acquire crucial information for genetic counseling and to support clinical decision-making in cases of suspected TADopathies., (© 2024. The Author(s).)

Pituitary gigantism is a rare manifestation of chronic growth hormone (GH) excess that begins before closure of the growth plates. Nearly half of patients with pituitary gigantism have an identifiable genetic cause. X-linked acrogigantism (X-LAG; 10% of pituitary gigantism) typically begins during infancy and can lead to the tallest individuals described. In the 10 years since its discovery, about 40 patients have been identified. Patients with X-LAG usually develop mixed GH and prolactin macroadenomas with occasional hyperplasia that secrete copious amounts of GH, and frequently prolactin. Circulating GH-releasing hormone is also elevated in a proportion of patients. X-LAG is caused by constitutive or sporadic mosaic duplications at chromosome Xq26.3 that disrupt the normal chromatin architecture of a topologically associating domain (TAD) around the orphan G-protein-coupled receptor, GPR101. This leads to the formation of a neo-TAD in which GPR101 overexpression is driven by ectopic enhancers ("TADopathy"). X-LAG has been seen in 3 families due to transmission of the duplication from affected mothers to sons. GPR101 is a constitutively active receptor with an unknown natural ligand that signals via multiple G proteins and protein kinases A and C to promote GH/prolactin hypersecretion. Treatment of X-LAG is challenging due to the young patient population and resistance to somatostatin analogs; the GH receptor antagonist pegvisomant is often an effective option. GH, insulin-like growth factor 1, and prolactin hypersecretion and physical overgrowth can be controlled before definitive adult gigantism occurs, often at the cost of permanent hypopituitarism., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Pituitary acrogigantism is a very rare disease that is caused by chronic growth hormone (GH) axis excess that begins during childhood and adolescence. As such, it represents one of the most severe manifestations of acromegaly. In most cases, acrogigantism is caused by a pituitary adenoma, but hyperplasia can also accompany the adenoma or rarely occur alone. Individual cases of pituitary acrogigantism due to peripheral neuroendocrine tumor-derived GH-secreting hormone excess that stimulates pituitary GH hypersecretion have been reported. About half of patients with pituitary acrogigantism carry an identifiable germline genetic alteration (pathogenic variants, copy number variations, alterations of topologically associated domains (TADs), mosaicism), making it one of the most genetically-determined endocrine tumors. Among the genetic causes, pathogenic variants in the AIP gene (30%), the TADopathy X-linked acrogigantism (10%), and McCune-Albright syndrome (5%) are the most frequent causes. Molecular alterations induced by these genetic and genomic changes lead to large aggressive somatotropinomas that occur at an early age, secrete abundant amounts of GH, and produce treatment-resistant increases in insulin-like growth factor 1. X-linked acrogigantism occurs in the first year of life and is usually present by the age of 36 months, whereas, McCune-Albright syndrome-related GH excess usually presents before 5 years of age. AIP-related pituitary acrogigantism has a median age at diagnosis of about 16 years of age. Patients with pituitary acrogigantism have a heavy burden of disease and a complex treatment journey; the need to control final height makes it imperative to provide a diagnosis and effective hormonal control as rapidly as possible. Multimodal therapy is often required, and this can be complicated by the need for medical therapies that are not labeled for use in the pediatric population., (© 2024 S. Karger AG, Basel.)

This manuscript presents some artistic and medical considerations about a representation of an individual with apparent dwarfism. He was found in Saqqara by the British Egyptologist James Edward Quibell, in 1910/11. The naked figure of this individual, Djeho, is carved in profile on the lid of his sarcophagus. He has a height of 120 cm and has characteristic clinical features suggesting achondroplasia., (© 2023. The Author(s), under exclusive licence to Italian Society of Endocrinology (SIE).)

Introduction: Prolactinomas are the most frequent type of pituitary adenoma encountered in clinical practice. Dopamine agonists (DA) like cabergoline typically provide sign/ symptom control, normalize prolactin levels and decrease tumor size in most patients. DA-resistant prolactinomas are infrequent and can occur in association with some genetic causes like MEN1 and pathogenic germline variants in the AIP gene (AIPvar)., Methods: We compared the clinical, radiological, and therapeutic characteristics of AIPvar-related prolactinomas (n=13) with unselected hospital-treated prolactinomas ("unselected", n=41) and genetically-negative, DA-resistant prolactinomas (DA-resistant, n=39)., Results: AIPvar-related prolactinomas occurred at a significantly younger age than the unselected or DA-resistant prolactinomas (p<0.01). Males were more common in the AIPvar (75.0%) and DA- resistant (49.7%) versus unselected prolactinomas (9.8%; p<0.001). AIPvar prolactinomas exhibited significantly more frequent invasion than the other groups (p<0.001) and exhibited a trend to larger tumor diameter. The DA-resistant group had significantly higher prolactin levels at diagnosis than the AIPvar group (p<0.001). Maximum DA doses were significantly higher in the AIPvar and DA-resistant groups versus unselected. DA-induced macroadenoma shrinkage (>50%) occurred in 58.3% in the AIPvar group versus 4.2% in the DA-resistant group (p<0.01). Surgery was more frequent in the AIPvar and DA- resistant groups (43.8% and 61.5%, respectively) versus unselected (19.5%: p<0.01). Radiotherapy was used only in AIPvar (18.8%) and DA-resistant (25.6%) groups., Discussion: AIPvar confer an aggressive phenotype in prolactinomas, with invasive tumors occurring at a younger age. These characteristics can help differentiate rare AIPvar related prolactinomas from DA-resistant, genetically-negative tumors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Vroonen, Beckers, Camby, Cuny, Beckers, Jaffrain-Rea, Cogne, Naves, Ferriere, Romanet, Elenkova, Karhu, Brue, Barlier, Pétrossians and Daly.)

Introduction: Pituitary adenomas (PAs) are common, usually benign tumors of the anterior pituitary gland which, for the most part, have no known genetic cause. PAs are associated with major clinical effects due to hormonal dysregulation and tumoral impingement on vital brain structures. PAM encodes a multifunctional protein responsible for the essential C-terminal amidation of secreted peptides., Methods: Following the identification of a loss-of-function variant (p.Arg703Gln) in the peptidylglycine a-amidating monooxygenase (PAM) gene in a family with pituitary gigantism, we investigated 299 individuals with sporadic PAs and 17 familial isolated PA kindreds for PAM variants. Genetic screening was performed by germline and tumor sequencing and germline copy number variation (CNV) analysis., Results: In germline DNA, we detected seven heterozygous, likely pathogenic missense, truncating, and regulatory SNVs. These SNVs were found in sporadic subjects with growth hormone excess (p.Gly552Arg and p.Phe759Ser), pediatric Cushing disease (c.-133T>C and p.His778fs), or different types of PAs (c.-361G>A, p.Ser539Trp, and p.Asp563Gly). The SNVs were functionally tested in vitro for protein expression and trafficking by Western blotting, splicing by minigene assays, and amidation activity in cell lysates and serum samples. These analyses confirmed a deleterious effect on protein expression and/or function. By interrogating 200,000 exomes from the UK Biobank, we confirmed a significant association of the PAM gene and rare PAM SNVs with diagnoses linked to pituitary gland hyperfunction., Conclusion: The identification of PAM as a candidate gene associated with pituitary hypersecretion opens the possibility of developing novel therapeutics based on altering PAM function., Competing Interests: AB, AD, FF, CS, and GT hold a patent on the GPR101 gene and its function US Patent No. 10,350,273, Treatment of Hormonal Disorders of Growth. CS holds patents on technologies involving PRKAR1A and related genes causing adrenal, pituitary, and other tumors. In addition, his laboratory has received research funding support by Pfizer Inc. for investigations on growth hormone–producing pituitary adenomas. CS has also consulted within the last 12 months with Lundbeck Pharmaceuticals and Sync, LLC, and is currently employed by ELPEN Pharmaceuticals. AB and AD have received research funding from Pfizer Inc. and Novo-Nordisk. M-LJ-R is part of the advisory board of Recordati Rare diseases since 2022. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Trivellin, Daly, Hernández-Ramírez, Araldi, Tatsi, Dale, Fridell, Mittal, Faucz, Iben, Li, Vitali, Stojilkovic, Kamenicky, Villa, Baussart, Chittiboina, Toro, Gahl, Eugster, Naves, Jaffrain-Rea, de Herder, Neggers, Petrossians, Beckers, Lania, Mains, Eipper and Stratakis.)

Infertility in couples is a common problem, with both female and male factors contributing to similar extents. Severe, congenital disorders affecting fertility are, however, rare. While folliculogenesis and spermatogenesis are generally orchestrated via different mechanisms, some genetic anomalies can impair both female and male gametogenesis. Minichromosome maintenance complex component 9 (MCM9) is involved in DNA repair and mutations of the MCM9 gene have been previously reported in females with premature ovarian insufficiency (POI). MCM9 is also an emerging cancer risk gene. We performed next-generation and Sanger sequencing of fertility and related genes and hormonal and imaging studies in a kindred whose members had POI and disordered spermatogenesis. We identified a homozygous pathogenic MCM9 variant, c.394C>T (p.Arg132*) in three sisters affected by POI due to ovarian dysgenesis and their brother who had normal pubertal development but suffered from non-obstructive azoospermia. Testicular biopsy revealed Sertoli cell-only testicular histopathology. No evidence of early onset cancer was found in the homozygotic family members, but they were all young (<30 years) at the time of the study. In the male patient the homozygous MCM9 variant led to normal pubertal development and hormonal levels but caused a Sertoli-cell-only syndrome with non-obstructive azoospermia. In the homozygous females studied, the clinical, hormonal, and gonadal phenotypes revealed ovarian dysgenesis consistent with previous reports. Active screening for potential colorectal and other cancer risks in the homozygotic MCM9 subjects has been instigated.

Context: Ectopic acromegaly is a consequence of rare neuroendocrine tumors (NETs) that secrete GHRH. This abnormal GHRH secretion drives GH and IGF-1 excess, with a clinical presentation similar to classical pituitary acromegaly. Identifying the underlying cause for the GH hypersecretion in the setting of ectopic GHRH excess is, however, essential for proper management both of acromegaly and the NET. Owing to the rarity of NETs, the imaging characteristics of the pituitary in ectopic acromegaly have not been analyzed in depth in a large series., Objective: Characterize pituitary magnetic resonance imaging (MRI) features at baseline and after NET treatment in patients with ectopic acromegaly., Design: Multicenter, international, retrospective., Setting: Tertiary referral pituitary centers., Patients: Thirty ectopic acromegaly patients having GHRH hypersecretion., Intervention: None., Main Outcome Measure: MRI characteristics of pituitary gland, particularly T2-weighted signal., Results: In 30 patients with ectopic GHRH-induced acromegaly, we found that most patients had hyperplastic pituitaries. Hyperplasia was usually moderate but was occasionally subtle, with only small volume increases compared with normal ranges for age and sex. T2-weighted signal was hypointense in most patients, especially in those with hyperplastic pituitaries. After treatment of the NET, pituitary size diminished and T2-weighted signal tended to normalize., Conclusions: This comprehensive study of pituitary MRI characteristics in ectopic acromegaly underlines the utility of performing T2-weighted sequences in the MRI evaluation of patients with acromegaly as an additional tool that can help to establish the correct diagnosis., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Screening studies have established genetic risk profiles for diseases such as multiple endocrine neoplasia type 1 (MEN1) and pheochromocytoma-paraganglioma (PPGL). Founder effects play an important role in the regional/national epidemiology of endocrine cancers, particularly PPGL. Founder effects in the Netherlands have been described for various diseases, some of which established themselves in South Africa due to Dutch emigration. The role of Dutch founder effects in South Africa has not been explored in PPGL., Design: We performed a single-center study in South Africa of the germline genetic causes of isolated/syndromic neuroendocrine tumors., Methods: Next-generation panel, Sanger sequencing and multiplex ligand-dependent probe amplification for endocrine neoplasia risk genes., Results: From a group of 13 patients, we identified 6 with PPGL, 4 with sporadic or familial isolated pituitary adenomas, and 3 with clinical MEN1; genetic variants were identified in 9/13 cases. We identified the Dutch founder exon 3 deletion in SDHB in two apparently unrelated individuals with distinct ethnic backgrounds that had metastatic PPGL. Asymptomatic carriers with this Dutch founder SDHBexon 3 deletion were also identified. Other PPGL patients had variants in SDHB, and SDHD and three MEN1variants were identified among MEN1 and young-onset pituitary adenoma patients., Conclusions: This is the first identification of a Dutch founder effect for PPGL in South Africa. Awareness of the presence of this exon 3 SDHB deletion could promote targeted screening at a local level. Insights into PPGL genetics in South Africa could be achieved by studying existing patient databases for Dutch founder mutations in SDHx genes.

Pituitary adenomas (PAs) are intracranial tumors associated with significant morbidity due to hormonal dysregulation, mass effects and have a heavy treatment burden. Growth hormone (GH)-secreting PAs (somatotropinomas) cause acromegaly-gigantism. Genetic forms of somatotropinomas due to germline AIP mutations (AIPmut+) have an early onset and are aggressive and resistant to treatment with somatostatin analogs (SSAs), including octreotide. The molecular underpinnings of these clinical features remain unclear. We investigated the role of miRNA dysregulation in AIPmut+ vs AIPmut- PA samples by array analysis. miR-34a and miR-145 were highly expressed in AIPmut+ vs AIPmut- somatotropinomas. Ectopic expression of AIPmut (p.R271W) in Aip -/- mouse embryonic fibroblasts (MEFs) upregulated miR-34a and miR-145, establishing a causal link between AIPmut and miRNA expression. In PA cells (GH3), miR-34a overexpression promoted proliferation, clonogenicity, migration and suppressed apoptosis, whereas miR-145 moderately affected proliferation and apoptosis. Moreover, high miR-34a expression increased intracellular cAMP, a critical mitogenic factor in PAs. Crucially, high miR-34a expression significantly blunted octreotide-mediated GH inhibition and antiproliferative effects. miR-34a directly targets Gnai2 encoding Gαi2, a G protein subunit inhibiting cAMP production. Accordingly, Gαi2 levels were significantly lower in AIPmut+ vs AIPmut- PA. Taken together, somatotropinomas with AIP mutations overexpress miR-34a, which in turn downregulates Gαi2 expression, increases cAMP concentration and ultimately promotes cell growth. Upregulation of miR-34a also impairs the hormonal and antiproliferative response of PA cells to octreotide. Thus, miR-34a is a novel downstream target of mutant AIP that promotes a cellular phenotype mirroring the aggressive clinical features of AIPmut+ acromegaly., (© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of Union for International Cancer Control.)

Most pancreatic neuroendocrine neoplasms (pNEN) occur sporadically but they can also occur as part of multiple endocrine neoplasia type 1 (MEN1). MAX was originally described as an inherited pheochromocytoma-paraganglioma risk gene, but also has recently been implicated in pituitary tumorigenesis. Here we describe the first case of a pNEN associated with an inherited MAX gene deletion in a family with endocrine tumors. The patient was a male carrier of an intragenic exon 3 deletion inherited from his father who had recurrent pheochromocytomas and a macroprolactinoma. The patient underwent screening and hormonal studies but no pheochromocytoma-paraganglioma, pituitary or renal tumors were identified. However, abdominal magnetic resonance imaging (MRI) identified a 1 cm lesion in body of the pancreas. The lesion was hyperintense on T2-weighted signal, and there was hyperfixation of the tumor on 68Ga-DOTANOC PET-CT images. No biochemical evidence of pancreatic hormone excess was identified. Following a guided biopsy, a pathological diagnosis of a low grade pNEN was made and immunohistochemistry showed loss of MAX nuclear staining. Genetic analysis of the tumor tissue indicated copy number neutral loss of heterozygosity consistent with uniparental disomy. This is the first reported case of a MAX deletion associated pNEN and strengthens the argument that MAX may represent an inheritable multiple endocrine neoplasia risk gene. Further analysis of germline and somatic MAX mutations/deletions in large cohorts of unexplained NEN cases could help clarify the potential role of MAX in NEN etiology., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Background: In acromegaly, chronic growth hormone (GH) and insulin-like growth factor-1 (IGF-1) exacerbate comorbidities in multiple organs. Differentiated thyroid carcinoma (DTC) has been reported as being a comorbid condition in acromegaly. Acromegaly is usuallysporadic, but 5% of cases may be genetic. The most frequent inheritable form of acromegaly is related to germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene. Epidemiological data on the relationship between active acromegaly, its familial forms and DTC are sparse. We present the investigation of a FIPA family (familial isolated pituitary adenoma) with homogeneous acromegaly and 6 sporadic acromegaly patients with DTC., Patients and Methods: A study of 59 acromegaly patients assessed thyroid nodules on ultrasound and fine-needle aspiration biopsy following the ATA 2015 criteria. We diagnosed 7 differentiated thyroid carcinomas. Resected thyroid carcinoma tissues were stained using an anti-AIP antibody. Analysis of germline and tumor-derived DNA for variants in the AIP and MEN1 genes were performed in the FIPA kindred., Results: We describe one FIPA patient and 6 sporadic acromegaly cases with DTC. The FIPA family (AIP mutation negative) consisted of two sisters, one of whom had a DTC with intermediate risk and incomplete structural response to therapy. In our study, DTC in sporadic acromegaly had a low recurrence rate (6/6), and excellent response to therapy (6/6). Immunohistochemistry for AIP showed similar or increased staining intensity in DTC versus normal thyroid tissue., Conclusion: In our cohort of sporadic and familial forms of acromegaly with DTC, AIP did not appear to influence thyroid cancer progression., (Copyright © 2020. Published by Elsevier Masson SAS.)

Growth hormone (GH) is a key modulator of growth and GH over-secretion can lead to gigantism. One form is X-linked acrogigantism (X-LAG), in which infants develop GH-secreting pituitary tumors over-expressing the orphan G-protein coupled receptor, GPR101. The role of GPR101 in GH secretion remains obscure. We studied GPR101 signaling pathways and their effects in HEK293 and rat pituitary GH3 cell lines, human tumors and in transgenic mice with elevated somatotrope Gpr101 expression driven by the rat Ghrhr promoter (Ghrhr Gpr101 ). Here, we report that Gpr101 causes elevated GH/prolactin secretion in transgenic Ghrhr Gpr101 mice but without hyperplasia/tumorigenesis. We show that GPR101 constitutively activates not only G s , but also G q/11 and G 12/13 , which leads to GH secretion but not proliferation. These signatures of GPR101 signaling, notably PKC activation, are also present in human pituitary tumors with high GPR101 expression. These results underline a role for GPR101 in the regulation of somatotrope axis function.

Pituitary adenomas are usually nonmalignant, but have a heavy burden on patients and health care systems. Increased availability of MRI has led to an increase in incidentally found pituitary lesions and clinically relevant pituitary adenomas. Epidemiologic studies show that pituitary adenomas are increasing in incidence (between 3.9 and 7.4 cases per 100,000 per year) and prevalence (76 to 116 cases per 100,000 population) in the general population (approximately 1 case per 1000 of the general population). Most new cases diagnosed are prolactinomas and nonsecreting pituitary adenomas. Most clinically relevant pituitary adenomas occur in females, but pituitary adenomas are clinically heterogeneous., Competing Interests: Disclosure The work was supported in part by grants from the FIRS funds of the CHU de Liège and by the JABBS Foundation, UK., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Context: First-generation somatostatin receptor ligands (fg-SRLs) represent the mainstay of medical therapy for acromegaly, but they provide biochemical control of disease in only a subset of patients. Various pretreatment biomarkers might affect biochemical response to fg-SRLs., Objective: To identify clinical predictors of the biochemical response to fg-SRLs monotherapy defined as biochemical response (insulin-like growth factor (IGF)-1 ≤ 1.3 × ULN (upper limit of normal)), partial response (>20% relative IGF-1 reduction without normalization), and nonresponse (≤20% relative IGF-1 reduction), and IGF-1 reduction., Design: Retrospective multicenter study., Setting: Eight participating European centers., Methods: We performed a meta-analysis of participant data from 2 cohorts (Rotterdam and Liège acromegaly survey, 622 out of 3520 patients). Multivariable regression models were used to identify predictors of biochemical response to fg-SRL monotherapy., Results: Lower IGF-1 concentration at baseline (odds ratio (OR) = 0.82, 95% confidence interval (CI) 0.72-0.95 IGF-1 ULN, P = .0073) and lower bodyweight (OR = 0.99, 95% CI 0.98-0.99 kg, P = .038) were associated with biochemical response. Higher IGF-1 concentration at baseline (OR = 1.40, (1.19-1.65) IGF-1 ULN, P ≤ .0001), the presence of type 2 diabetes (oral medication OR = 2.48, (1.43-4.29), P = .0013; insulin therapy OR = 2.65, (1.02-6.70), P = .045), and higher bodyweight (OR = 1.02, (1.01-1.04) kg, P = .0023) were associated with achieving partial response. Younger patients at diagnosis are more likely to achieve nonresponse (OR = 0.96, (0.94-0.99) year, P = .0070). Baseline IGF-1 and growth hormone concentration at diagnosis were associated with absolute IGF-1 reduction (β = 0.90, standard error (SE) = 0.02, P ≤ .0001 and β  = 0.002, SE = 0.001, P = .014, respectively)., Conclusion: Baseline IGF-1 concentration was the best predictor of biochemical response to fg-SRL, followed by bodyweight, while younger patients were more likely to achieve nonresponse., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Familial isolated pituitary adenoma (FIPA) is one of the most frequent conditions associated with an inherited presentation of pituitary tumors. FIPA can present with pituitary adenomas of any secretory/non-secretory type. Mutations in the gene for the aryl-hydrocarbon receptor interacting protein (AIP) have been identified in approximately 20% of FIPA families and are the most frequent cause (29%) of pituitary gigantism. Pituitary tumors in FIPA are larger, occur at a younger age and display more aggressive characteristics and evolution than sporadic adenomas. This aggressiveness is especially marked in FIPA kindreds with AIP mutations. Special attention should be paid to young patients with pituitary gigantism and/or macroadenomas, as AIP mutations are prevalent in these groups. Duplications on chromosome Xq26.3 involving the gene GPR101 lead to X-linked acrogigantism (X-LAG), a syndrome of pituitary gigantism beginning in early childhood; three kindreds with X-LAG have presented in the setting of FIPA. Management of pituitary adenomas in the setting of FIPA, AIP mutations and GPR101 duplications is often more complex than in sporadic disease due to early onset disease, aggressive tumor growth and resistance to medical therapy.

We recently described X-linked acrogigantism (X-LAG) in sporadic cases of infantile gigantism and a few familial cases of pituitary gigantism in the context of the disorder known as familial isolated pituitary adenomas. X-LAG cases with early onset gigantism (in infants or toddlers) shared copy number gains (CNG) of the distal long arm of chromosome X (Xq26.3). In all patients described to date with Xq26.3 CNG and acro-gigantism, the only coding gene sequence shared by all chromosomal defects was that of GPR101. GPR101 is a class A, rhodopsin-like orphan guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) with no known endogenous ligand. We review what is known about GPR101, specifically its expression profile in human and animal models, the evidence supporting causation of X-LAG and possibly other roles, including its function in growth, puberty and appetite regulation, as well as efforts to identify putative ligands.

Pituitary adenomas are benign tumors with variable functional characteristics that can have a significant impact on patients. The majority arise sporadically, but an inherited genetic susceptibility is increasingly being recognized. Recent advances in genetics have widened the scope of our understanding of pituitary tumorigenesis. The clinical and genetic characteristics of pituitary adenomas that develop in the setting of germline-mosaic and somatic GNAS mutations (McCune-Albright syndrome and sporadic acromegaly), germline MEN1 mutations (multiple endocrine neoplasia type 1), and germline PRKAR1A mutations (Carney complex) have been well described. Non-syndromic familial cases of isolated pituitary tumors can occur as familial isolated pituitary adenomas (FIPA); mutations/deletions of the AIP gene have been found in a minority of these. Genetic alterations in GPR101 have been identified recently as causing X-linked acro-gigantism (X-LAG) leading to very early-onset pediatric gigantism. Associations of pituitary adenomas with other tumors have been described in syndromes like multiple endocrine neoplasia type 4, pheochromocytoma-paraganglioma with pituitary adenoma association (3PAs) syndrome and some of their genetic causes have been elucidated. The genetic etiologies of a significant proportions of sporadic corticotropinomas have recently been identified with the discovery of USP8 and USP48 mutations. The elucidation of genetic and molecular pathophysiology in pituitary adenomas is a key factor for better patient management and effective follow-up., Competing Interests: The authors declare that they have no conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)

Clinically-relevant pituitary adenomas occur in about 1:1000 of the general population, but only about 5% occur in a known genetic or familial setting. Familial isolated pituitary adenomas (FIPA) are one of the most important inherited settings for pituitary adenomas and the most frequent genetic cause is a germline mutation in the aryl hydrocarbon receptor-interacting protein ( AIP ) gene. AIP mutations lead to young-onset macroadenomas that are difficult to treat. Most are growth hormone secreting tumors, but all other secretory types can exist and the clinical profile of affected patients is variable. We present an overview of the current understanding of AIP mutation-related pituitary disease and illustrate various key clinical factors using examples from one of the largest AIP mutation-positive FIPA families identified to date, in which six mutation-affected members with pituitary disease have been diagnosed. We highlight various clinically significant features of FIPA and AIP mutations, including issues related to patients with acromegaly, prolactinoma, apoplexy and non-functioning pituitary adenomas. The challenges faced by these AIP mutation-positive patients due to their disease and the long-term outcomes in older patients are discussed. Similarly, the pitfalls encountered due to incomplete penetrance of pituitary adenomas in AIP- mutated kindreds are discussed.

Purpose: Germline mutations in the aryl-hydrocarbon receptor interacting protein (AIP) have been identified often in the setting of familial isolated pituitary adenoma (FIPA). To date there is no strong evidence linking germline AIP mutations to other neoplasms apart from the pituitary. Our primary objective was to investigate the prevalence of AIP gene mutations and mutations in genes that have been associated with neuroendocrine tumors in series of tumors from patients presenting with both pituitary adenomas and differentiated thyroid carcinomas (DTCs)., Methods: Pathology samples were retrieved from all pituitary adenomas in patients with concomitant DTCs, including one with a known germline AIP variant. Subsequently, two additional patients with known germline AIP variants were included, of which one presented only with a follicular thyroid carcinoma (FTC)., Results: In total, 17 patients (14 DTCs and 15 pituitary adenomas) were investigated by targeted next generation sequencing (NGS). The pituitary tumor samples revealed no mutations, while among the thyroid tumor samples BRAF (6/14, 42.9%) was the most frequently mutated gene, followed by NRAS (3/11, 27.3%). In one AIP-mutated FIPA kindred, the AIP-variant c.853C>T; p.Q285* was confirmed in the FTC specimen, including evidence of loss of heterozygosity (LOH) at the AIP locus in the tumor DNA., Conclusion: Although most observed variants in pituitary adenomas and DTCs were similar to those of sporadic DTCs, we confirmed in one AIP mutation-positive case the AIP-variant and LOH at this locus in an FTC specimen, which raises the potential role of the AIP mutation as a rare initiating event.

Most pituitary adenomas are sporadic, but 3-5% can occur in a family and hereditary context. This is the case of multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC) and familial isolated pituitary adenomas (FIPA). FIPA is an infrequent condition that occurs in a family context, not associated with MEN type1 or CNC. FIPA kindred can be homogeneous (all adenomas affected in the family having the same tumor phenotype) or heterogeneous (different tumor phenotypes in the affected members). We describe a Congolese family in which two sisters and a cousin were diagnosed with a prolactinoma (homogenous FIPA) at the ages of 29, 32 and 40 years, respectively. The patients presented with macroadenomas at the time of diagnosis, non-invasive tumors and good biological response to cabergoline treatment (maximum dose of 1.5 mg/weekly). Of these two sisters, one went through a pregnancy without complications. Because no MEN1 and CNC clinical and biochemical features were detected during the 12-year follow-up, these genes were not investigated. The genetic analysis of the aryl hydrocarbon receptor interacting protein (AIP) was normal. As nearly 80% of patients with FIPA do not have a mutation in the AIP gene, future studies in these families are required to identify other affected genes involved in their physiopathology.

Purpose: Parathyroid cancer is a rare tumor associated with poor prognosis particularly when disseminated. While chemotherapy and/or radiotherapy are of no clinical value in disseminated disease, immunotherapy should be considered., Subject and Results: A patient with CDC73-associated metastatic parathyroid carcinoma was treated with combined anti-hPTH immunotherapy and surgery., Conclusions: Following five courses of anti-hPTH immunotherapy and subsequent surgery, a 12-year long remission of disseminated parathyroid cancer is reported. This case further supports the ever-expanding spectrum of cancers that may benefit from immunotherapy.

Pituitary adenomas are frequently occurring neoplasms that produce clinically significant disease in 1:1000 of the general population. The pathogenesis of pituitary tumors is a matter of interest as it could help to improve diagnosis and treatment. Until recently, however, disruptions in relatively few genes were known to predispose to pituitary tumor formation. In the last decade, several more genes and pathways have been described. Germline pathogenic variants in the aryl hydrocarbon receptor-interacting protein (AIP) gene were found in familial or sporadic pituitary adenomas, usually with an aggressive clinical course. Cyclin-dependent kinase inhibitor 1B (CDKN1B) pathogenic variants lead to multiple endocrine neoplasia type 4 (MEN4) syndrome, in which pituitary adenomas can occur. Xq26.3 duplications involving the gene GPR101 cause X-linked acrogigantism. The pheochomocytoma and/or paraganglioma with pituitary adenoma association (3PAs) syndrome suggests that pathogenic variants in the genes of the succinate dehydrogenase complex or MYC-associated factor X (MAX) might be involved in pituitary tumorigenesis. New recurrent somatic alterations were also discovered in pituitary adenomas, such as, ubiquitin-specific protease 8 (USP8) and USP48 pathogenic variants in corticotropinomas. The aim of the present review is to provide an overview of the genetic pathophysiology of pituitary adenomas and their clinical relevance.

Prolactinomas are the most commonly encountered pituitary adenomas in the clinical setting. While most can be controlled by dopamine agonists, a subset of prolactinomas are dopamine-resistant and very aggressive. In such tumors, the treatment of choice is neurosurgery and radiotherapy, with or without temozolomide. Here, we report a patient with an highly aggressive, dopamine-resistant prolactinoma, who only achieved biochemical and tumor control during pasireotide long-acting release (PAS-LAR) therapy, a second-generation somatostatin receptor ligand (SRL). Interestingly, cystic degeneration, tumor cell necrosis or both was observed after PAS-LAR administration suggesting an antitumor effect. This case shows that PAS-LAR therapy holds clinical potential in selective aggressive, dopamine-resistant prolactinomas that express somatostatin (SST) receptor subtype 5 and appears to be a potential new treatment option before starting temozolomide. In addition, PAS-LAR therapy may induce cystic degeneration, tumor cell necrosis or both in prolactinomas.

Testosterone production by the fetal testis depends on a functional relationship between hCG and the LH/chorionic gonadotropin receptor (LHCGR). Failure of the receptor to correctly respond to its ligand leads to impaired sexual differentiation in males. A phenotypically female patient with pubertal delay had a 46,XY karyotype and was diagnosed with 46,XY disorder of sex development (DSD). Novel compound heterozygous LHCGR mutations were found in the signal peptide: a duplication p.L10&#95;Q17dup of maternal origin, and a deletion (p.K12&#95;L15del) and a p.L16Q missense mutation of paternal origin. cAMP production was very low for both the deletion and duplication mutations and was halved for the missense mutant. The duplication and missense mutations were both expressed intracellularly, but at very low levels at the cell membrane; they were most likely retained in the endoplasmic reticulum. The deletion mutant had a very limited intracellular expression, indicating impaired biosynthesis. There was reduced expression of all three mutants, which was most marked for the deletion mutation. There was also decreased protein expression of all three mutant receptors. In the deletion mutation, the presence of a lower-molecular-weight band corresponding to LHCGR monomer, probably due to lack of glycosylation, and a lack of bands corresponding to dimers/oligomers suggests absent ER entry. This novel case of 46,XY DSD illustrates how different LHCGR signal peptide mutations led to complete receptor inactivation by separate mechanisms. The study underlines the importance of specific regions of signal peptides and expands the spectrum of LHCGR mutations.

Acromegaly is a rare disease due to chronic excess growth hormone (GH) and IGF-1. Aryl hydrocarbon receptor interacting protein (AIP) mutations are associated with an aggressive, inheritable form of acromegaly that responds poorly to SST2-specific somatostatin analogs (SSA). The role of pasireotide, an SSA with affinity for multiple SSTs, in patients with AIP mutations has not been reported. We studied two AIP mutation positive acromegaly patients with early-onset, invasive macroadenomas and inoperable residues after neurosurgery. Patient 1 came from a FIPA kindred and had uncontrolled GH/IGF-1 throughout 10 years of octreotide/lanreotide treatment. When switched to pasireotide LAR, he rapidly experienced hormonal control which was associated with marked regression of his tumor residue. Pasireotide LAR was stopped after >10 years due to low IGF-1 and he maintained hormonal control without tumor regrowth for >18 months off pasireotide LAR. Patient 2 had a pituitary adenoma diagnosed when aged 17 that was not cured by surgery. Chronic pasireotide LAR therapy produced hormonal control and marked tumor shrinkage but control was lost when switched to octreotide. Tumor immunohistochemistry showed absent AIP and SST2 staining and positive SST5. Her AIP mutation positive sister developed a 2.5 cm follicular thyroid carcinoma aged 21 with tumoral loss of heterozygosity at the AIP locus and absent AIP staining. Patients 1 and 2 required multi-modal therapy to control diabetes. On stopping pasireotide LAR after >10 years of treatment, Patient 1's glucose metabolism returned to baseline levels. Long-term pasireotide LAR therapy can be beneficial in some AIP mutation positive acromegaly patients that are resistant to first-generation SSA.

Background: Pituitary adenomas have a high disease burden due to tumor growth/invasion and disordered hormonal secretion. Germline mutations in genes such as MEN1 and AIP are associated with early onset of aggressive pituitary adenomas that can be resistant to medical therapy., Aims: We performed a retrospective screening study using published risk criteria to assess the frequency of AIP and MEN1 mutations in pituitary adenoma patients in a tertiary referral center., Methods: Pituitary adenoma patients with pediatric/adolescent onset, macroadenomas occurring ≤30 years of age, familial isolated pituitary adenoma (FIPA) kindreds and acromegaly or prolactinoma cases that were uncontrolled by medical therapy were studied genetically. We also assessed whether immunohistochemical staining for AIP (AIP-IHC) in somatotropinomas was associated with somatostatin analogs (SSA) response., Results: Fifty-five patients met the study criteria and underwent genetic screening for AIP/MEN1 mutations. No mutations were identified and large deletions/duplications were ruled out using MLPA. In a cohort of sporadic somatotropinomas, low AIP-IHC tumors were significantly larger (P = 0.002) and were more frequently sparsely granulated (P = 0.046) than high AIP-IHC tumors. No significant relationship between AIP-IHC and SSA responses was seen., Conclusions: Germline mutations in AIP/MEN1 in pituitary adenoma patients are rare and the use of general risk criteria did not identify cases in a large tertiary-referral setting. In acromegaly, low AIP-IHC was related to larger tumor size and more frequent sparsely granulated subtype but no relationship with SSA responsiveness was seen. The genetics of pituitary adenomas remains largely unexplained and AIP screening criteria could be significantly refined to focus on large, aggressive tumors in young patients.

Clinically relevant pituitary adenomas are present in about 1 per 1,000 of the general population and prolactinomas are by far the most common clinical subtype of pituitary adenomas. Usually prolactinomas affect premenopausal women and present with typical symptoms of menstrual disturbance and/or galactorrhea. They are generally managed with dopamine agonists to restore fertility and to control symptoms and tumor size. In a subset of prolactinomas, however, management remains challenging. Studies in recent years have identified the factors related to dopamine agonist resistance, such as male sex, genetic features, and aggressive tumor behavior. Certain other patient groups represent particular challenges for management, such as pediatric patients and pregnant women. Treatment with dopamine agonists is usually safe and effective, and adverse effects such as clinically relevant cardiac valvular complications and impulse control disorders may occur in isolated instances. A number of important disease characteristics of prolactinomas remain to be explained, such as the difference in sex prevalence before and after menopause, the higher prevalence of macroadenomas in older males, and the biochemical mechanisms of resistance to dopaminergic agonists., (© 2019 S. Karger AG, Basel.)

In the general population, height is determined by a complex interplay between genetic and environmental factors. Pituitary gigantism is a rare but very important subgroup of patients with excessive height, as it has an identifiable and clinically treatable cause. The disease is caused by chronic growth hormone and insulin-like growth factor 1 secretion from a pituitary somatotrope adenoma that forms before the closure of the epiphyses. If not controlled effectively, this hormonal hypersecretion could lead to extremely elevated final adult height. The past 10 years have seen marked advances in the understanding of pituitary gigantism, including the identification of genetic causes in ~50% of cases, such as mutations in the AIP gene or chromosome Xq26.3 duplications in X-linked acrogigantism syndrome. Pituitary gigantism has a male preponderance, and patients usually have large pituitary adenomas. The large tumour size, together with the young age of patients and frequent resistance to medical therapy, makes the management of pituitary gigantism complex. Early diagnosis and rapid referral for effective therapy appear to improve outcomes in patients with pituitary gigantism; therefore, a high level of clinical suspicion and efficient use of diagnostic resources is key to controlling overgrowth and preventing patients from reaching very elevated final adult heights.