Mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene are associated with pituitary adenomas that usually occur as familial isolated pituitary adenomas (FIPA). Detailed pathological and tumor genetic data on AIP mutation-related pituitary adenomas are not sufficient. Non-identical twin females presented as adolescents to the emergency department with severe progressive headache caused by large pituitary macroadenomas require emergency neurosurgery; one patient had incipient pituitary apoplexy. Post-surgically, the patients were found to have silent somatotrope adenomas on pathological examination. Furthermore, the light microscopic, immunohistochemical, and electron microscopic studies demonstrated tumors of virtually identical characteristics. The adenomas were accompanied by multiple areas of pituitary hyperplasia, which stained positively for GH, indicating somatotrope hyperplasia. Genetic analyses of the FIPA kindred revealed a novel E216X mutation of the AIP gene, which was present in both the affected patients and the unaffected father. Molecular analysis of surgical specimens revealed loss of heterozygosity (LOH) in the adenoma but showed that LOH was not present in the hyperplastic pituitary tissue from either patient. AIP immunostaining confirmed normal staining in the hyperplastic tissue and decreased staining in the adenoma in the tumors from both patients. These results demonstrate that patients with AIP germline mutation can present with silent somatotrope pituitary adenomas. The finding of somatotrope hyperplasia unaccompanied by AIP LOH suggests that LOH at the AIP locus might be a late event in a potential progression from hyperplastic to adenomatous tissue.
Chiara Villa, Maria Stefania Lagonigro, Flavia Magri, Maria Koziak, Marie-Lise Jaffrain-Rea, Raja Brauner, Jerome Bouligand, Marie Pierre Junier, Federico Di Rocco, Christian Sainte-Rose, Albert Beckers, François Xavier Roux, Adrian F Daly and Luca Chiovato
Laura C Hernández-Ramírez, Ryhem Gam, Nuria Valdés, Maya B Lodish, Nathan Pankratz, Aurelio Balsalobre, Yves Gauthier, Fabio R Faucz, Giampaolo Trivellin, Prashant Chittiboina, John Lane, Denise M Kay, Aggeliki Dimopoulos, Stephan Gaillard, Mario Neou, Jérôme Bertherat, Guillaume Assié, Chiara Villa, James L Mills, Jacques Drouin and Constantine A Stratakis
The CABLES1 cell cycle regulator participates in the adrenal–pituitary negative feedback, and its expression is reduced in corticotropinomas, pituitary tumors with a largely unexplained genetic basis. We investigated the presence of CABLES1 mutations/copy number variations (CNVs) and their associated clinical, histopathological and molecular features in patients with Cushing’s disease (CD). Samples from 146 pediatric (118 germline DNA only/28 germline and tumor DNA) and 35 adult (tumor DNA) CD patients were screened for CABLES1 mutations. CNVs were assessed in 116 pediatric CD patients (87 germline DNA only/29 germline and tumor DNA). Four potentially pathogenic missense variants in CABLES1 were identified, two in young adults (c.532G > A, p.E178K and c.718C > T, p.L240F) and two in children (c.935G > A, p.G312D and c.1388A > G, and p.D463G) with CD; no CNVs were found. The four variants affected residues within or close to the predicted cyclin-dependent kinase-3 (CDK3)-binding region of the CABLES1 protein and impaired its ability to block cell growth in a mouse corticotropinoma cell line (AtT20/D16v-F2). The four patients had macroadenomas. We provide evidence for a role of CABLES1 as a novel pituitary tumor-predisposing gene. Its function might link two of the main molecular mechanisms altered in corticotropinomas: the cyclin-dependent kinase/cyclin group of cell cycle regulators and the epidermal growth factor receptor signaling pathway. Further studies are needed to assess the prevalence of CABLES1 mutations among patients with other types of pituitary adenomas and to elucidate the pituitary-specific functions of this gene.
Albert Beckers, Maya Beth Lodish, Giampaolo Trivellin, Liliya Rostomyan, Misu Lee, Fabio R Faucz, Bo Yuan, Catherine S Choong, Jean-Hubert Caberg, Elisa Verrua, Luciana Ansaneli Naves, Tim D Cheetham, Jacques Young, Philippe A Lysy, Patrick Petrossians, Andrew Cotterill, Nalini Samir Shah, Daniel Metzger, Emilie Castermans, Maria Rosaria Ambrosio, Chiara Villa, Natalia Strebkova, Nadia Mazerkina, Stéphan Gaillard, Gustavo Barcelos Barra, Luis Augusto Casulari, Sebastian J Neggers, Roberto Salvatori, Marie-Lise Jaffrain-Rea, Margaret Zacharin, Beatriz Lecumberri Santamaria, Sabina Zacharieva, Ee Mun Lim, Giovanna Mantovani, Maria Chaira Zatelli, Michael T Collins, Jean-François Bonneville, Martha Quezado, Prashant Chittiboina, Edward H Oldfield, Vincent Bours, Pengfei Liu, Wouter W de Herder, Natalia Pellegata, James R Lupski, Adrian F Daly and Constantine A Stratakis
X-linked acrogigantism (X-LAG) is a new syndrome of pituitary gigantism, caused by microduplications on chromosome Xq26.3, encompassing the gene GPR101, which is highly upregulated in pituitary tumors. We conducted this study to explore the clinical, radiological, and hormonal phenotype and responses to therapy in patients with X-LAG syndrome. The study included 18 patients (13 sporadic) with X-LAG and microduplication of chromosome Xq26.3. All sporadic cases had unique duplications and the inheritance pattern in two families was dominant, with all Xq26.3 duplication carriers being affected. Patients began to grow rapidly as early as 2–3 months of age (median 12 months). At diagnosis (median delay 27 months), patients had a median height and weight standard deviation scores (SDS) of >+3.9 SDS. Apart from the increased overall body size, the children had acromegalic symptoms including acral enlargement and facial coarsening. More than a third of cases had increased appetite. Patients had marked hypersecretion of GH/IGF1 and usually prolactin, due to a pituitary macroadenoma or hyperplasia. Primary neurosurgical control was achieved with extensive anterior pituitary resection, but postoperative hypopituitarism was frequent. Control with somatostatin analogs was not readily achieved despite moderate to high levels of expression of somatostatin receptor subtype-2 in tumor tissue. Postoperative use of adjuvant pegvisomant resulted in control of IGF1 in all five cases where it was employed. X-LAG is a new infant-onset gigantism syndrome that has a severe clinical phenotype leading to challenging disease management.