Impact of hyperparathyroidism on allograft histology and function after kidney transplantation: Rethinking its causal role in graft dysfunction.

INTRODUCTION: The causal relationship between hyperparathyroidism and kidney graft dysfunction remains inconclusive. Applying Bradford-Hill's temporality and consistency causation principles, we assessed the effect of parathyroid hormone (iPTH) on graft histology and eGFR trajectory on kidney transplant recipients (KTRs) with normal time-zero graft biopsies. METHODS: Retrospective cohort study evaluating the effect of hyperparathyroidism on interstitial fibrosis and tubular atrophy (IF/TA) development in 1232 graft biopsies. Pre-transplant hyperparathyroidism was categorized by KDIGO or KDOQI criteria, and post-transplant hyperparathyroidism by iPTH >1× and >2× the URL 1 year after transplantation. RESULTS: We included 325 KTRs (56% female, age 38 ± 13 years, follow-up 4.2 years [IQR: 2.7-5.8]). Based on pre-transplant iPTH levels, 26% and 66% exceeded the KDIGO and KDOQI targets, respectively. There were no significant differences in the development of >25% IF/TA between KTRs with pre-transplant iPTH levels above and within target range according to KDIGO (53% vs. 62%, P = .16, HR.94 [95% CI:.67-1.32]) and KDOQI (60% vs. 60%, P = 1.0, HR 1.19 [95% CI:.88-1.60]) criteria. Similarly, there were no differences when using 1 year post-transplant iPTH cut-offs > 88 pg/mL (58% vs. 64%, P = .33) and > 176 pg/mL (55% vs. 62%, P = .19). After adjusting for confounders, no significant differences were observed in eGFR trajectories among the iPTH strata. CONCLUSION: In young KTRs who received a healthy graft, no association was found between increased pre- and post-transplant iPTH levels and graft dysfunction, as assessed histologically and through eGFR trajectory. The concept of hyperparathyroidism as a risk factor for graft dysfunction in recipients at low risk requires reevaluation.

Insights into Hyperparathyroidism-Jaw Tumour Syndrome: From Endocrine Acumen to the Spectrum of CDC73 Gene and Parafibromin-Deficient Tumours.

A total of 1 out of 10 patients with primary hyperparathyroidism (PHP) presents an underlying genetic form, such as multiple endocrine neoplasia types 1, 2A, etc., as well as hyperparathyroidism-jaw tumour syndrome (HJT). We aimed to summarise the recent data, thus raising more awareness regarding HJT, from the clinical perspective of PHP in association with the challenges and pitfalls of CDC73 genetic testing and parafibromin staining. This narrative review included a sample-focused analysis from the past decade according to a PubMed search. We identified 17 original human studies (≥4 patients per article). The mean age at disease onset was between 20.8 and 39.5 years, while the largest study found that 71% of patients had HJT recognised before the age of 30. Males and females seemed to be equally affected, in contrast with sporadic PHP. PHP represented the central manifestation of HJT, occurring as the first manifestation in up to 85% of HJT cases. A biochemistry panel found a mean serum calcium level above the level of 12 mg/dL in PHP. PTH was elevated in HJT as well, with average values of at least 236.6 pg/mL. The most frequent pathological type in PHP was a parathyroid adenoma, but the incidence of a parathyroid carcinoma was much higher than in non-HJT cases (15% of all parathyroid tumours), with the diagnosis being established between the age of 15 and 37.5. In some families up to 85% of carriers suffered from a parathyroid carcinoma thus indicating that certain CDC73 pathogenic variants may harbour a higher risk. An important issue in HJT was represented by the parafibromin profile in the parathyroid tumours since in HJT both parathyroid adenomas and carcinomas might display a deficient immunoreactivity. Another frequent manifestation in HJT was ossifying fibromas of the jaw (affecting 5.4% to 50% of patients; the largest study found a prevalence of 15.4%). HJT was associated with a wide variety of kidney lesion (mostly: kidney cysts, with a prevalence of up to 75%, and renal tumours involved in 19% of patients). The risk of uterine lesions seemed increased in HJT, especially with concern to leiomyomas, adenofibromas, and adenomyosis. The underlying pathogenic mechanisms and the involvement of CDC73 pathogenic variants and parafibromin expression are yet to be explored. Currently, the heterogeneous expression of parafibromin status and, the wide spectrum of CDC73 mutations including the variety of clinical presentations in HJT, make it difficult to predict the phenotype based on the genotype. The central role of HJT-PHP is, however, the main clinical element, while the elevated risk of parathyroid carcinoma requires a special awareness.

Multiple endocrine neoplasia type 2: A review.

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

A Diagnostic Journey.

We describe the case of a patient who came with features suggestive of diabetic ketoacidosis. On further evaluation of DKA, we found that it was caused by acute pancreatitis. This acute pancreatitis was found to be caused by hypercalcemia, which was in turn due to primary hyperparathyroidism. Imaging studies done for hyperparathyroidism revealed a thyroid nodule which later turned out to be malignant. This patient was also incidentally found to have hypertrophic obstructive cardiomyopathy.

A Fatal Case of Metastatic Pulmonary Calcification during the Puerperium.

We present an unusual case of a fatal respiratory failure in a young woman developed two weeks after she gave birth at home. Circumstantial and clinical features of the case were strongly suggestive for a 'classical' septic origin of the respiratory symptoms. Autopsy, together with histopathological and immunohistochemical analyses allowed demonstrating a massive calcium redistribution consisting of an important osteolysis, especially from cranial bones and abnormal accumulation in lungs and other organs. Such physiopathology was driven by a primary hyperparathyroidism secondary to a parathyroid carcinoma as demonstrated by immunohistochemistry. This very rare case is furthermore characterised by a regular pregnancy course, ended with the birth of a healthy new-born. A complex interaction between pregnancy physiology and hyperparathyroidism might be hypothesised, determining the discrepancy between the relative long period of wellness and the tumultuous cascade occurred in the puerperium.

Interrelated role of Klotho and calcium-sensing receptor in parathyroid hormone synthesis and parathyroid hyperplasia.

The pathogenesis of parathyroid gland hyperplasia is poorly understood, and a better understanding is essential if there is to be improvement over the current strategies for prevention and treatment of secondary hyperparathyroidism. Here we investigate the specific role of Klotho expressed in the parathyroid glands (PTGs) in mediating parathyroid hormone (PTH) and serum calcium homeostasis, as well as the potential interaction between calcium-sensing receptor (CaSR) and Klotho. We generated mouse strains with PTG-specific deletion of Klotho and CaSR and dual deletion of both genes. We show that ablating CaSR in the PTGs increases PTH synthesis, that Klotho has a pivotal role in suppressing PTH in the absence of CaSR, and that CaSR together with Klotho regulates PTH biosynthesis and PTG growth. We utilized the tdTomato gene in our mice to visualize and collect PTGs to reveal an inhibitory function of Klotho on PTG cell proliferation. Chronic hypocalcemia and ex vivo PTG culture demonstrated an independent role for Klotho in mediating PTH secretion. Moreover, we identify an interaction between PTG-expressed CaSR and Klotho. These findings reveal essential and interrelated functions for CaSR and Klotho during parathyroid hyperplasia.

Intra-operative parathyroid hormone evaluation is superior to frozen section analysis in parathyroid surgery.

BACKGROUND: Surgery is currently the only treatment option for patients with primary hyperparathyroidism (PHPT). Recently, minimally invasive parathyroidectomy (MIP) has begun to replace traditional bilateral neck exploration (BNE). OBJECTIVE: The aim of this study is to compare the results of parathyroidectomies performed in our hospital over the past decade that were guided by intra-operative parathyroid hormone (IOPTH) sampling or frozen section (FS) analysis. MATERIAL AND METHODS: Data on 697 patients who underwent parathyroidectomies in the Department of Endocrine Surgery, Dokuz Eylul University between January 2005 and 2018 were included in this study. Patients with malignancies other than thyroid papillary microcarcinoma and parathyroid cancer were excluded from the study. RESULTS: The concomitant use of neck ultrasound (US) and technetium 99m Sestamibi (99mTc MIBI) scintigraphy successfully localized the hyperfunctioning parathyroid glands in nearly 96% of cases. As compared with the IOPTH group, the operation time was longer in the FS group (p < 0.001), and the need for postoperative calcium (Ca) supplementation was higher (p < 0.001). The duration of hospitalization (days) was significantly higher in the FS group (4.2 ± 3.4 vs. 2.6 ± 1.9) as compared with that in the IOPTH group (p < 0.001). In addition, the recurrence rate in the FS group was significantly higher than that in the IPOTH group (p = 0.002). CONCLUSION: IOPTH sampling is a safe and effective method when performed by experienced surgeons and with appropriate preoperative screening. This study emphasizes that IOPTH sampling. We believe that the success in parathyroid surgery is due to three factors: correct indication, accurate localization and experienced surgeon.

Physical Activity-Dependent Regulation of Parathyroid Hormone and Calcium-Phosphorous Metabolism.

Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the effects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise. Altered PTH metabolism underlies hyperparathyroidism and hypoparathyroidism, the complications of which affect the organs involved in calcium and phosphorous metabolism (bone and kidney) and other body systems as well. Exercise affects PTH expression and secretion by altering the circulating levels of calcium and phosphate. In turn, PTH responds directly to exercise and exercise-induced myokines. Here, we review the main concepts of the regulation of PTH expression and secretion under physiological conditions, in acute and chronic exercise, and in relation to PTH-related disorders.

Disruption of the PTHLH regulatory landscape results in features consistent with hyperparathyroid disease.

Parathyroid hormone like hormone (PTHLH) signaling is essential for the proper formation of bone and its elevation or disruption has been directly implicated in several different skeletal dysplasias. We report a patient with a 2.802 Mb deletion upstream of the PTHLH coding sequence who presents with multiple fractures, metaphyseal changes, and overall features consistent with hyperparathyroid like disease. Analysis of the deleted region revealed the loss of putative regulatory regions adjacent to PTHLH and the possible gain of a limb enhancer. Furthermore, PTHLH expression appeared to be mis-regulated in fibroblasts derived from the patient. Altogether, we find that the disruption of the regulatory landscape of PTHLH likely results in its inappropriate expression and this novel clinical presentation.

Hypoalbuminemia differently affects the serum bone turnover markers in hemodialysis patients.

Renal osteodystrophy (ROD) represents bone disorders related to chronic kidney disease (CKD) and several bone biomarkers are used clinically to predict ROD in CKD and hemodialysis (HD) patients. Serum albumin associates with inflammation other than nutritional status in these patients. Chronic inflammation is proved to relate with bone loss, however, the influence of hypoalbuminemia on bone biomarkers is still unclear. In this study, we evaluated the pattern of bone biomarker changes and further studied the influence of hypoalbuminemia on these biomarkers. A total of 300 maintenance HD patients were evaluated and 223 HD patients were included in the study. The patients were grouped according to serum parathyroid hormone (PTH) levels (PTH ≤150 pg/mL, PTH 150-300 pg/mL, PTH 300-600 pg/mL and PTH >600 pg/mL). Bone biomarkers and inflammatory markers were measured and their relation with PTH levels was determined. Significantly increased interleukin-6 (IL-6) and lower albumin levels were noted among PTH>600 pg/mL group. Bone turnover markers were significantly higher in PTH >600 pg/mL group (p< 0.05). Hypoalbuminemia significantly increased the fibroblast growth factor-23 (FGF-23) and procollagen type 1N-terminal propeptide (P1NP) in PTH ≤150 pg/mL, PTH 150-300 pg/mL, PTH 300-600 pg/mL groups, whereas no such relation was noted among PTH> 600 ng/dL group. In conclusion, hypoalbuminemia represents a chronic inflammation which differently relates to bone turnover markers according to serum PTH levels in SHPT patients. Thus, serum albumin measurement should be considered in determining bone disorders among these patients.

PETC/CT with 18F-Choline localizes hyperfunctioning parathyroid adenomas equally well in normocalcemic hyperparathyroidism as in overt hyperparathyroidism.

PURPOSE: Identification of pathologic parathyroid glands in primary hyperparathyroidism, traditionally based on neck ultrasound (US) and/or 99mTc-Sestamibi scintigraphy, can be challenging. PET/CT with 18F-Fluorocholine (18F-FCH) might improve the detection of pathologic parathyroid glands. We aimed at comparing the diagnostic performance of 18F-FCH-PET/CT with that of dual-phase dual-isotope parathyroid scintigraphy and neck US. METHODS: Thirty-four consecutive patients with primary hyperparathyroidism were prospectively enrolled, 7 had normocalcemic hyperparathyroidism, and 27 had classic hypercalcemic hyperparathyroidism. All patients underwent high-resolution neck US, dual-phase dual-isotope 99mTc-Pertechnetate/99mTc-Sestamibi scintigraphy, and 18F-FCH-PET/CT. RESULTS: In the whole patients' group, the detection rates of the abnormal parathyroid gland were 68% for neck US, 71% for 18F-FCH-PET/CT, and only 15% for 99mTc-Sestamibi scintigraphy. The corresponding figures in normocalcemic and hypercalcemic hyperparathyroidism were 57 and 70% for neck US, 70 and 71% for 18F-FCH-PET/CT, and 0 and 18% for 99mTc-Sestamibi scintigraphy, respectively. In the 17 patients in whom the abnormal parathyroid gland was identified, either at surgery or at fine needle aspiration cytology/biochemistry, the correct detection rate was 82% for neck US, 89% for 18F-FCH-PET/CT, and only 17% for 99mTc-Sestamibi scintigraphy. CONCLUSIONS: 18F-FCH-PET/CT can be considered a first-line imaging technique for the identification of pathologic parathyroid glands in patients with normocalcemic and hypercalcemic hyperparathyroidism, even when the parathyroid volume is small.

The prevalence and anatomy of parathyroid glands: a meta-analysis with implications for parathyroid surgery.

PURPOSE: The anatomy of parathyroid glands (PTG) is highly variable in the population. The aim of this study was to conduct a systematic analysis on the prevalence and location of PTG in healthy and hyperparathyroidism (HPT) patients. METHODS: An extensive search of the major electronic databases was conducted to identify all studies that reported relevant data on the number of PTG per patient and location of PTG. The data was extracted from the eligible studies and pooled into a meta-analysis. RESULTS: The overall analysis of 26 studies (n = 7005 patients; n = 23,519 PTG) on the number of PTG showed that 81.4% (95% CI 65.4-85.8) of patients have four PTG. A total of 15.9% of PTG are present in ectopic locations, with 11.6% (95% CI 5.1-19.1) in the neck and 4.3% (95% CI 0.7-9.9) in mediastinum. The subgroup analysis of ectopic PTG showed that 51.7% of ectopic PTG in the neck are localized in retroesophageal/paraesophageal space or in the thyroid gland. No significant differences were observed between the healthy and HPT patients and cadaveric and intraoperative studies. CONCLUSIONS: Knowledge regarding the prevalence, location, and anatomy of PTG is essential for surgeons planning for and carrying out parathyroidectomies, as any unidentified PTG, either supernumerary or in ectopic location, can result in unsuccessful treatment and need for reoperation.

Characterization of a novel CDC73 gene mutation in a hyperparathyrodism-jaw tumor patient affected by parathyroid carcinoma in the absence of somatic loss of heterozygosity.

Hyperparathyrodism-jaw tumor (HPT-JT) syndrome is an autosomal dominant disorder. Loss of function of the cell division cycle protein 73 homolog (CDC73) gene is responsible for the syndrome. This gene encodes an ubiquitously expressed 531 amino acid protein, parafibromin, that acts as a tumor suppressor. Loss of heterozygosity (LOH) of the CDC73 locus in many HPT-JT associated parathyroid tumors from patients with germline mutation is in accordance with Knudson's "two-hit" model for hereditary cancer. A 41-year-old man with mandible ossifying fibroma suffered from severe hypercalcemia due to parathyroid carcinoma (PC). Genetic analysis was performed to evaluate germinal and somatic CDC73 gene mutation as well as real-time qRT-PCR to quantify CDC73 mRNA, miR-155 and miR-664 expression levels. Immunohistochemistry and Western blotting (WB) assay were carried out to evaluate parafibromin protein expression. A novel heterozygous nonsense mutation, c.191-192 delT, was identified in the CDC73 gene. No CDC73 LOH was found in PC tissue, nor any differences in expression levels for CDC73 gene, miR-155 and miR-664 between PC and parathyroid adenoma control tissues. On the contrary, both immunohistochemistry and WB assay showed an approximate 90% reduction of parafibromin protein expression in PC. In conclusion, this study describes a novel germinal mutation, c.191-192 delT, in the CDC73 gene. Despite normal CDC73 gene expression, we found a significant decrease in parafibromin. We hypothesize that a gene silencing mechanism, possibly induced by microRNA, could play a role in determining somatic post-transcriptional inactivation of the wild type CDC73 allele.

Resveratrol inhibits parathyroid hormone-induced apoptosis in human aortic smooth muscle cells by upregulating sirtuin 1.

BACKGROUND: Cardiovascular disease is the leading cause of death in patients with chronic kidney disease, so there is an urgent need to identify therapeutic targets to control the progression of cardiovascular disease. Apoptosis of aortic smooth muscle cells can promote cardiovascular disease, but the role of parathyroid hormone (PTH) and sirtuin 1 in the pathophysiology of apoptosis is still unclear. METHODS: Cultured human aortic smooth muscle cells (HASMCs) were stimulated with 10-6, 10-8, or 10-10 mol/L PTH for different days, apoptosis was measured by flow cytometry and sirtuin 1 and Bcl-2 protein levels in cell extracts were analyzed by western blotting. HASMCs were stimulated with PTH (10-8 mol/L) and 50 or 100 µmol/L RES for 3 d, apoptosis was measured by flow cytometry and sirtuin 1 and Bcl-2 protein levels in cell extracts were analyzed by western blotting. RESULTS: We found that PTH decreased the expression of sirtuin 1 and Bcl-2, inducing apoptosis (p<.05). Resveratrol (RES), a sirtuin 1 agonist, inhibited PTH-induced apoptosis and restored Bcl-2 expression (p<.05). CONCLUSIONS: PTH induces apoptosis in HASMCs. Resveratrol inhibits PTH-induced apoptosis in HASMCs.

Intraoperative Probe-Based Confocal Endomicroscopy to Histologically Differentiate Thyroid From Parathyroid Tissue Before Resection.

BACKGROUND: Frozen section is the standard method to histologically distinguish parathyroid tissue from thyroid tissue during endocrine neck surgery. Frozen section can be time-consuming and costly. Its drawback is that it is to be performed only after the removal of a suspected pathological tissue. This study demonstrates the use of probe-based confocal laser endomicroscopy (pCLE) to confirm histology prior to tissue resection. DESIGN: A prospective, single-institution, nonrandomized study was conducted. No sample size calculation was performed for this observational trial. The primary objective was the description of histological rendering of normal and pathological tissues through pCLE. Real-time in vivo fluorescence microscopy imaging was performed with the CystoFlex UHD probe after intravenous injection of 2.5 mL of 10% fluorescein sodium. RESULTS: Eleven patients with hyperparathyroidism and thyroid conditions were included. A total of 104 videos showing thyroid, parathyroid, adipose tissue, muscle, laryngeal nerve, and lymph nodes were recorded. Videos were compared with visual information and pathological samples (when sampling was indicated). Thyroid tissue could be identified based on the presence of colloid follicles (intensely fluorescent area surrounded by a small ridge of low-fluorescence epithelial cells) including the pathognomonic aspect of resorption vacuole. Parathyroid tissue could be identified based on a regular, "diamond-shaped" capillary network encompassing parathyroid chief cells. Blinded reinterpretation of pCLE videos demonstrated an 89.3% sensitivity and a 90% specificity as compared with histology in tissue recognition. CONCLUSION: This pilot study describes representative renderings of intraoperative pCLE to nontraumatically differentiate thyroid, parathyroid, and lymph nodes before surgical removal.

MANIFESTATIONS OF HYPERPARATHYROIDISM IN JUVENILE WHOOPING CRANES (GRUS AMERICANA).

Juvenile whooping cranes (Grus americana) raised for wild release were found to have an increased incidence of rib fractures at fledging in 2017 compared with the previous 16 years. Serum analysis showed 30-day-old juveniles in 2017 (n = 12) had significantly lower 25-hydroxyvitamin D3 and significantly higher parathyroid hormone concentrations than juveniles in 2010 (n = 6) with no history of rib fractures. Increased serum parathyroid hormone concentrations in the 2017 juveniles persisted to fledging age. Review of dietary and environmental management revealed that juveniles in 2017 were provided a commercial diet with a lower, and perhaps suboptimal, calcium:phosphorus ratio and experienced reduced time outdoors in the first month after hatch, presumably resulting in less ultraviolet B radiation exposure. Mild hyperparathyroidism in precocial whooping cranes may result when dietary constraints and/or outdoor access is compromised and manifest as rib fractures in the absence of traumatic injury.

Growing Human Parathyroids in a Microphysiological System: A Novel Approach to Understanding and Developing New Treatments for Hyperparathyroidism.

We developed a novel model for studying hyperparathyroidism by growing ex vivo 3-dimensional human parathyroids as part of a microphysiological system (MPS) that mimics human physiology. The purpose of this study was to validate the parathyroid portion of the MPS. We prospectively collected parathyroid tissue from 46 patients with hyperparathyroidism for growth into pseudoglands. We evaluated pseudogland architecture and calcium responsiveness. Following 2 weeks in culture, dispersed cells successfully coalesced into pseudoglands ∼500-700 µm in diameter that mimicked the appearance of normal parathyroid glands. Functionally, they also appeared similar to intact parathyroids in terms of organization and calcium-sensing receptor expression. Immunohistochemical staining for calcium-sensing receptor revealed 240-450/cell units of mean fluorescence intensity within the pseudoglands. Finally, the pseudoglands showed varying levels of calcium responsiveness, indicated by changes in parathyroid hormone (PTH) levels. In summary, we successfully piloted the development of a novel MPS for studying the effects of hyperparathyroidism on human organ systems. We are currently evaluating the effect of PTH on adverse remodeling of tissue engineered cardiac, skeletal, and bone tissue within the MPS.

[Clinical and morphological characteristics of parathyroid carcinoma]. / Kliniko-morfologicheskaia kharakteristika raka okoloshchitovidnoi zhelezy.

Parathyroid carcinoma (PTC) is a rare malignant tumor with the clinical manifestation of hyperparathyroidism, reliable morphological signs of invasive growth, and poor clinical prognosis. The differential diagnosis of PTC due to the rarity of this pathology, not always explicit morphological criteria, and the lack of a certain immunohistochemical panel is complex and needs further clarification. The paper summarizes an update on the clinical and morphological characteristics of PTC.

Large intragenic deletion of CDC73 (exons 4-10) in a three-generation hyperparathyroidism-jaw tumor (HPT-JT) syndrome family.

BACKGROUND: Inactivating mutations of CDC73 cause Hyperparathyroidism-Jaw Tumour syndrome (HPT-JT), Familial Isolated Hyperparathyroidism (FIHP) and sporadic parathyroid carcinoma. We conducted CDC73 mutation analysis in an HPT-JT family and confirm carrier status of the proband's daughter. METHODS: The proband had primary hyperparathyroidism (parathyroid carcinoma) and uterine leiomyomata. Her father and daughter had hyperparathyroidism (parathyroid adenoma) but no other manifestations of HPT-JT. CDC73 mutation analysis (sequencing of all 17 exons) and whole-genome copy number variation (CNV) analysis was done on leukocyte DNA of the three affecteds as well as the proband's unaffected sister. RESULTS: A novel deletion of exons 4 to 10 of CDC73 was detected by CNV analysis in the three affecteds. A novel insertion in the 5'UTR (c.-4_-11insG) that co-segregated with the deletion was identified. By in vitro assay the 5'UTR insertion was shown to significantly impair the expression of the parafibromin protein. Screening for the mutated CDC73 confirmed carrier status in the proband's daughter and the biochemistry and ultrasonography led to pre-emptive surgery and resolution of the hyperparathyroidism. CONCLUSIONS: A novel gross deletion mutation in CDC73 was identified in a three-generation HPT-JT family emphasizing the importance of including screening for large deletions in the molecular diagnostic protocol.

Primary hyperparathyroidism caused by enormous unilateral water-clear cell parathyroid hyperplasia.

BACKGROUND: Parathyroid water-clear cell hyperplasia (WCCH) and water-clear cell adenoma (WCCA) are rare causes of primary hyperparathyroidism. The frequency of WCCH seems to be less than 1% of all primary hyperplasia. CASE PRESENTATION: We report a 53-year-old woman with a large unilateral water clear cell parathyroid hyperplasia associated with primary hyperparathyroidism and severe osteoporosis. Ultrasonography showed a 5.4 cm multilobulated hypoechoic well defined mass localized in the lower half of the left thyroid lobe. Technetium sestamibi scanning showed a persistent very large area of increased activity possibly corresponding to a left inferior double parathyroid adenoma. At surgery, two large merged lobulated parathyroid glands were removed from the left superior and inferior aspects of the adjacent thyroid extending to the sub-clavicular area. Histopathology showed polygonal hyperplastic vacuolated cells with abundant water clear cytoplasm. The lesion had lack of capsule or rim of parathyroid tissue and immunohistochemistry was positive for PTH staining. These findings were consistent with diffused water clear cell hyperplasia. After parathyroidectomy, iPTH and calcium levels dropped immediately. CONCLUSION: The clinical presentation of the patients with water clear cells parathyroid content and hyperparathyroidism is indistinguishable from that of the more common causes of primary hyperparathyroidism of adenoma or hyperplasia and the diagnosis is made only on pathological examination. In conclusion, the distinction of water clear cell hyperplasia from water clear cell adenoma can be challenging in many cases, although clinically significant as far as treatment and follow-up.