Inactivating germline mutations of the CDKN1B gene encoding the nuclear cyclin-dependent kinase inhibitor P27kip1 protein have been reported in patients with multiple endocrine neoplasia type 4 (MEN4), a MEN1-like phenotype without MEN1 mutations. The aim of this study was to characterize in vitro the germline CDKN1B mutation c.374_375delCT (S125X) we detected in a patient with MEN4. The proband was affected by primary hyperparathyroidism due to multiglandular parathyroid involvement and gastro–entero–pancreatic tumors. We carried out subcellular localization experiments by transfection with plasmid vectors expressing the WT or mutant CDKN1B cDNA into the eukaryotic human cervix adenocarcinoma (HeLa) and GH3 cell lines. Results from western blotting studies indicated that fusion proteins were expressed at equal levels. The mutated protein was shorter compared with the WT protein and lacked the highly conserved C-terminal domain, which includes the bipartite nuclear localization signal at amino acids 152/153 and 166/168. In HeLa and GH3 cells, WT P27 localized in the nucleus, whereas the P27_S125X protein was retained in the cytoplasm, predicting the loss of tumor-suppressive function. The proband's tumoral parathyroid tissue did not show allelic loss, because both WT and mutant alleles were determined to be present by sequencing the somatic DNA. Immunohistochemistry revealed a complete loss of nuclear expression of P27 in a parathyroid adenoma, which had been removed by the second surgery in the patient. In conclusion, our results confirm the pathogenic role of the c.374_375delCT CDKN1B germline mutation in a patient with MEN4.
Elena Pardi, Stefano Mariotti, Natalia S Pellegata, Katiuscia Benfini, Simona Borsari, Federica Saponaro, Liborio Torregrossa, Antonello Cappai, Chiara Satta, Marco Mastinu, Claudio Marcocci, and Filomena Cetani
Elizaveta Mamedova, Natalya Mokrysheva, Evgeny Vasilyev, Vasily Petrov, Ekaterina Pigarova, Sergey Kuznetsov, Nikolay Kuznetsov, Liudmila Rozhinskaya, Galina Melnichenko, Ivan Dedov, and Anatoly Tiulpakov
Primary hyperparathyroidism (PHPT) is a relatively rare disorder among children, adolescents and young adults. Its development at an early age is suspicious for hereditary causes, though the need for routine genetic testing remains controversial.
To identify and describe hereditary forms of PHPT in patients with manifestation of the disease under 40 years of age.
We enrolled 65 patients with PHPT diagnosed before 40 years of age. Ten of them had MEN1 mutation, and PHPT in them was the first manifestation of multiple endocrine neoplasia type 1 syndrome.
The other fifty-five patients underwent next-generation sequencing (NGS) of a custom-designed panel of genes, associated with PHPT (MEN1, CASR, CDC73, CDKN1A, CDKN1B, CDKN1C, CDKN2A, CDKN2C, CDKN2D). In cases suspicious for gross CDC73 deletions multiplex ligation-dependent probe amplification was performed.
NGS revealed six pathogenic or likely pathogenic germline sequence variants: four in CDC73 c.271C>T (p.Arg91*), c.496C>T (p.Gln166*), c.685A>T (p.Arg229*) and c.787C>T (p.Arg263Cys); one in CASR c.3145G>T (p.Glu1049*) and one in MEN1 c.784-9G>A. In two patients, MLPA confirmed gross CDC73 deletions. In total, 44 sporadic and 21 hereditary PHPT cases were identified. Parathyroid carcinomas and atypical parathyroid adenomas were present in 8/65 of young patients, in whom CDC73 mutations were found in 5/8.
Hereditary forms of PHPT can be identified in up to 1/3 of young patients with manifestation of the disease at <40 years of age. Parathyroid carcinomas or atypical parathyroid adenomas in young patients are frequently associated with CDC73 mutations.
Luchuan Li, Baoyuan Li, Bin Lv, Weili Liang, Binbin Zhang, Qingdong Zeng, Andrew G Turner, and Lei Sheng
Multiple studies have reported the increased incidence of thyroid cancer in patients with primary hyperparathyroidism (PHPT). However, the underlying risk factors of concomitant thyroid cancer in patients with PHPT remain unknown. The primary aim of this study was to examine the records of patients with PHPT to identify characteristics that correlated with the presence of coexisting thyroid nodules, and which may have an implication for the prediction of thyroid cancer.
Medical records of consecutive patients with PHPT (n = 318) were reviewed from January 2010 to September 2020 in two tertiary medical centers in China. Patient clinicopathological and biological data were collected and analyzed.
Of a total of 318 patients with PHPT, 105 (33.0%) patients had thyroid nodules and 26 (8.2%) patients were concomitant with thyroid cancer. A total of 38 thyroid nodules taken from 26 patients were pathologically assessed to be well-differentiated papillary thyroid carcinoma (PTC), with 81% being papillary thyroid microcarcinoma (PTMC). In 79% (30/38) of these cancers, thyroid nodules were considered suspicious following preoperative ultrasound. Multinomial logistic regression analysis revealed that female gender was associated with increased risk of thyroid nodules (OR = 2.13, 95% CI: 1.13–3.99, P = 0.019), while lower log-transformed parathyroid hormone levels were an independent predictor of thyroid cancer in patients with PHPT (OR = 0.50, 95% CI: 0.26–0.93, P = 0.028).
In conclusion, we observed a relatively high prevalence of thyroid cancer in our cohort of Chinese patients with PHPT. Evaluation of thyroid nodules by preoperative ultrasound may be advisable in patients with PHPT, particularly for females and patients with modestly elevated serum parathyroid hormone levels.
Louise Vølund Larsen, Delphine Mirebeau-Prunier, Tsuneo Imai, Cristina Alvarez-Escola, Kornelia Hasse-Lazar, Simona Censi, Luciana A Castroneves, Akihiro Sakurai, Minoru Kihara, Kiyomi Horiuchi, Véronique Dorine Barbu, Francoise Borson-Chazot, Anne-Paule Gimenez-Roqueplo, Pascal Pigny, Stephane Pinson, Nelson Wohllk, Charis Eng, Berna Imge Aydogan, Dhananjaya Saranath, Sarka Dvorakova, Frederic Castinetti, Attila Patocs, Damijan Bergant, Thera P Links, Mariola Peczkowska, Ana O Hoff, Caterina Mian, Trisha Dwight, Barbara Jarzab, Hartmut P H Neumann, Mercedes Robledo, Shinya Uchino, Anne Barlier, Christian Godballe, and Jes Sloth Mathiesen
Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.
Design and methods
An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017.
Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4–1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis.
Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.
Laura P B Elbers, Marije Wijnberge, Joost C M Meijers, Dennis C W Poland, Dees P M Brandjes, Eric Fliers, and Victor E A Gerdes
Abnormal coagulation tests have been observed in patients with primary hyperparathyroidism (HPT) suggesting a prothrombotic effect of parathyroid hormone (PTH). Vitamin D deficiency (VIDD) is the most frequent cause of secondary HPT. Aim of our study was to investigate the influence of HPT secondary to moderate-to-severe VIDD and vitamin D replacement on the coagulation and fibrinolysis system.
Subjects and methods
Prospective cohort study of patients with vitamin D <25 nmol/L with and without HPT, and a control group of patients on vitamin D suppletion. At baseline and after 2 months of vitamin D suppletion (900,000 IU in 2 months), endocrine and coagulation markers were measured.
59 patients with VIDD of which 34 had secondary HPT and 36 controls were included. After 2 months of suppletion, vitamin D increased by 399% (VIDD with HPT), 442% (all patients with VIDD) and 6% (controls). PTH decreased by 34% (VIDD with HPT, P < 0.01 for decrease), 32% (all VIDD, P < 0.01) and increased by 8% in the controls (P-values: <0.01 for relative changes between VIDD with HPT or all VIDD patients vs controls). Relative changes in PT, aPTT, fibrinogen, Von Willebrand factor, factors VII, VIII and X, thrombin generation, TAFI, clot-lysis time and d-dimer were not different between patients with VIDD with HPT or all VIDD vs controls.
Secondary HPT due to VIDD does not have a prothrombotic effect. In contrast with previous reports, PTH does not seem to influence coagulation or fibrinolysis, which is relevant because of the high prevalence of VIDD.
Xiao-Ping Qi, Jian-Zhong Peng, Xiao-Wei Yang, Zhi-Lie Cao, Xiu-Hua Yu, Xu-Dong Fang, Da-Hong Zhang, and Jian-Qiang Zhao
Cutaneous lichen amyloidosis (CLA) has been reported in some multiple endocrine neoplasia type 2A (MEN 2A) families affected by specific germline RET mutations C634F/G/R/W/Y or V804M, as a characteristic of the clinical manifestation in ‘MEN 2A with CLA’, one of four variants of MEN 2A, which was strictly located in the scapular region of the upper back.
This study reports a large south-eastern Chinese pedigree with 17 individuals carrying the MEN 2A-harboring germline C611Y (c.1832G>A) RET mutation by Sanger sequencing. One individual presented MEN 2A-related clinical features, including typical CLA in the interscapular region; another individual exhibited neurological pruritus and scratching in the upper back but lacked CLA skin lesions. Both subjects presented with CLA or pruritic symptoms several years before the onset of medullary thyroid carcinoma (MTC) and/or pheochromocytoma. The remaining 15 RET mutation carriers did not exhibit CLA; of these, one presented with MTC and pheochromocytoma, nine with MTC only, two with elevated serum calcitonin and three younger subjects with normal serum calcitonin levels. This family’s clinical data revealed a later diagnosis of MTC (mean age, 45.9 (range: 23–73) years), a lower penetrance of pheochromocytoma (2/17, 11.8%) and CLA (1/17, 5.9%). However, no hyperparathyroidism and Hirschsprung disease were reported in this family.
Summary and Conclusions
This is the first description of a family with MEN 2A-related CLA due to a germline RET C611Y mutation, which might exhibit a novel and diversified genotype–phenotype spectrum in MEN 2A.
Kelly Brewer, Isabel Nip, Justin Bellizzi, Jessica Costa-Guda, and Andrew Arnold
Primary hyperparathyroidism is most often caused by a sporadic single-gland parathyroid adenoma (PTA), a tumor type for which cyclin D1 is the only known and experimentally validated oncoprotein. However, the molecular origins of its frequent overexpression have remained mostly elusive. In this study, we explored a potential tumorigenic mechanism that could increase cyclin D1 stability through a defect in molecules responsible for its degradation.
We examined two tumor suppressor genes known to modulate cyclin D1 ubiquitination, PRKN and FBXO4 (FBX4), for evidence of classic two-hit tumor suppressor inactivation within a cohort of 82 PTA cases. We examined the cohort for intragenic inactivating and splice site mutations by Sanger sequencing and for locus-associated loss of heterozygosity (LOH) by microsatellite analysis.
We identified no evidence of bi-allelic tumor suppressor inactivation of PRKN or FBXO4 via inactivating mutation or splice site perturbation, neither in combination with nor independent of LOH. Among the 82 cases, we encountered previously documented benign single nucleotide polymorphisms (SNPs) in 35 tumors at frequencies similar to those reported in the germlines of the general population. Eight cases exhibited intragenic LOH at the PRKN locus, in some cases extending to cover at least an additional 1.7 Mb of chromosome 6q25-26. FBXO4 was not affected by LOH.
The absence of evidence for specific bi-allelic inactivation in PRKN and FBXO4 in this sizeable cohort suggests that these genes only rarely, if ever, serve as classic driver tumor suppressors responsible for the growth of PTAs.
Sondra O’Callaghan and Hanford Yau
Palliation of symptoms related to malignancy-associated hypercalcemia (MAH) is essential and clinically meaningful for patients, given the continued poor prognosis, with high morbidity and mortality associated with this disease process. Historically, agents have been temporizing, having no impact on patient morbidity nor survival. We suggest that cinacalcet can be an efficacious agent to be taken orally, reducing patients’ time in the hospital/clinic settings. It is well-tolerated and maintains serum calcium levels in the normal range, while targeted cancer treatments can be employed. This has a direct, major impact on morbidity. Maintaining eucalcemia can increase quality of life, while allowing targeted therapies time to improve survival. Given that our case (and others) showed calcium reduction in MAH, there is promising evidence that cinacalcet can be more widely employed in this setting. Future consideration should be given to studies addressing the efficacy of cinacalcet in calcium normalization, improvement of quality of life, and impact on survival in patients with MAH. Though the exact mechanism of action for cinacalcet’s reduction in calcium in this setting is not currently known, we can still afford patients the possible benefit from it.
Ursula M M Costa, Carla R P Oliveira, Roberto Salvatori, José A S Barreto-Filho, Viviane C Campos, Francielle T Oliveira, Ivina E S Rocha, Joselina L M Oliveira, Wersley A Silva, and Manuel H Aguiar-Oliveira
GH and its principal mediator IGF1 have important effects on metabolic and cardiovascular (CV) status. While acquired GH deficiency (GHD) is often associated with increased CV risk, the consequences of congenital GHD are not known. We have described a large group of patients with isolated GHD (IGHD) due to a homozygous mutation (c.57+1G>A) in the GH releasing hormone receptor gene, and shown that adult GH-naïve individuals have no evidence of clinically evident premature atherosclerosis. To test whether subclinical atherosclerosis is anticipated in untreated IGHD, we performed a cross-sectional study of 25 IGHD and 27 adult controls matched for age and gender. A comprehensive clinical and biochemical panel and coronary artery calcium scores were evaluated by multi-detector tomography. Height, weight, IGF1, homeostasis model assessment of insulin resistance, creatinine and creatininekinase were lower in the IGHD group. Median and interquartile range of calcium scores distribution was similar in the two groups: IGHD 0(0) and control 0(4.9). The vast majority of the calcium scores (20 of 25 IGHD (80%) and 18 of 27 controls (66.6%)) were equal to zero (difference not significant). There was no difference in the calcium scores classification. None of IGHD subjects had minimal calcification, which were present in four controls. Three IGHD and four controls had mild calcification. There were two IGHD individuals with moderate calcification and one control with severe calcification. Our study provides evidence that subjects with congenital isolated lifetime and untreated severe IGHD do not have accelerated subclinical coronary atherosclerosis.
Tomás P Griffin, Caroline M Joyce, Sumaya Alkanderi, Liam M Blake, Derek T O’Keeffe, Delia Bogdanet, Md Nahidul Islam, Michael C Dennedy, John E Gillan, John J Morrison, Timothy O’Brien, John A Sayer, Marcia Bell, and Paula M O’Shea
Inactivating mutations in CYP24A1, encoding vitamin D-24-hydroxylase, can lead to an accumulation of active vitamin D metabolites and consequent hypercalcaemia. Patient (infantile and adult) presentation is varied and includes mild-severe hypercalcaemia, hypercalciuria, nephrocalcinosis and nephrolithiasis. This study aimed to characterize the clinical and biochemical phenotypes of a family with two CYP24A1 missense variants.
The proband and seven family members underwent detailed clinical and biochemical evaluation. Laboratory measurements included serum calcium, intact parathyroid hormone (iPTH), vitamin D metabolites and urine calcium and creatinine.
The proband presented during the second trimester of a planned pregnancy with flu-like symptoms. Laboratory tests showed elevated adjusted calcium of 3.27 (upper reference limit (URL: 2.30) mmol/L), suppressed iPTH (<6 ng/L), elevated 25(OH)D (264 (URL: 55) nmol/L) and elevated 1,25(OH)D (293 (URL: <280) pmol/L). Ionized calcium was 1.55 (URL: 1.28) mmol/L. Sanger sequencing revealed two heterozygous missense variants in the CYP24A1: p.(Arg439Cys), R439C and p.(Trp275Arg), W275R. The proband’s brother and sister had the same genotype. The brother had intermittent hypercalcaemia and hypervitaminosis D. Only the sister had a history of nephrolithiasis. The proband’s daughter and two nephews were heterozygous for the R439C variant. The proband and her brother frequently had elevated 25(OH)D:24,25(OH)2D ratios (>50) during follow-up.
W275R is a new pathogenic CYP24A1 mutation in compound heterozygotic form with R439C in this family.