Primary hyperparathyroidism in Chinese children and adolescents: A single-centre experience at Peking Union Medical College Hospital

Variable presentation and outcomes of primary hyperparathyroidism in children and adolescents

OBJECTIVES

Primary hyperparathyroidism (PHPT) in paediatric and adolescent age group presents with some unique challenges for clinicians. While the disease in the adult counterparts presents with symptoms which are described quite extensively in literature, children/adolescents have manifestations which are quite different and severe compared to the former. The present case series aimed to highlight the peculiarities of presentation of PHPT in children and adolescents.

CASE PRESENTATION

In this case series, we present experience of 5 cases of PHPT in children and adolescents from our centre. We compared our data with the data already available in literature. We have also described salient presenting features of PHPT in individuals less than 19 years old previously reported in literature and pointed out the specificities of this disease at this age group.

CONCLUSIONS

PHPT in children and adolescents should be considered as a separate entity compared to that in adults, given its unique features, such as rachitic features, and severity of different presenting phenotypes. Persistence of rachitic features despite vitamin D correction, pancreatitis, bilateral nephrolithiasis and otherwise unexplained psychiatric abnormalities of insidious onset require greater clinical vigilance and serum/urine calcium testing to rule out this uncommon yet possible entity.

The pathophysiology of hypophosphatemia

After identification of fibroblast growth factor (FGF) 23 as the pivotal regulator of chronic serum inorganic phosphate (Pi) levels, the etiology of disorders causing hypophosphatemic rickets/osteomalacia has been clarified, and measurement of intact FGF23 serves as a potent tool for differential diagnosis of chronic hypophosphatemia. Additionally, measurement of bone-specific alkaline phosphatase (BAP) is recommended to differentiate acute and subacute hypophosphatemia from chronic hypophosphatemia. This article divides the etiology of chronic hypophosphatemia into 4 groups: A. FGF23 related, B. primary tubular dysfunction, C. disturbance of vitamin D metabolism, and D. parathyroid hormone 1 receptor (PTH1R) mediated. Each group is further divided into its inherited form and acquired form. Topics for each group are described, including "ectopic FGF23 syndrome," "alcohol consumption-induced FGF23-related hypophosphatemia," "anti-mitochondrial antibody associated hypophosphatemia," and "vitamin D-dependent rickets type 3." Finally, a flowchart for differential diagnosis of chronic hypophosphatemia is introduced.

Pediatric Neuroendocrine Neoplasia of the Parathyroid Glands: Delving into Primary Hyperparathyroidism

Our objective was to overview the most recent data on primary hyperparathyroidism (PHP) in children and teenagers from a multidisciplinary perspective. Methods: narrative review based on full-length, English-language papers (from PubMed, between January 2020 and July 2023). Results: 48 papers (14 studies of ≥10 subjects/study, and 34 case reports/series of <10 patients/study). Study-sample-based analysis: except for one case-control study, all of the studies were retrospective, representing both multicenter (n = 5) and single-center (n = 7) studies, and cohort sizes varied from small (N = 10 to 19), to medium-sized (N = 23 to 36) and large (N = 63 to 83); in total, the reviewed studies covered 493 individuals with PHP. Case reports/series (n = 34, N = 41): the mean ages studied varied from 10.2 to 14 years in case reports, and the mean age was 17 years in case series. No clear female predominance was identified, unlike that observed in the adult population. Concerning the assessments, there were four major types of endpoints: imaging data collection, such as ultrasound, 99mTc Sestamibi, or dual-phase computed tomography (CT); gene testing/familial syndrome identification; preoperative findings; and exposure to surgical outcome/preoperative drugs, like cinacalcet, over a 2.2-year median (plus two case reports of denosumab used as an off-label calcium-lowering agent). Single-gland cases (representing 85% of sporadic cases and 19% of genetic PHP cases) showed 100% sensitivity for neck ultrasounds, with 98% concordance with 99mTc Sestamibi, as well as a 91% sensitivity for dual-phase CT, with 25% of the lesions being ectopic parathyroids (mostly mediastinal intra-thymic). Case reports included another 9/41 patients with ectopic parathyroid adenomas, 3/41 with parathyroid carcinomas, and 8/41 subjects with brown tumors. Genetic PHP (which has a prevalence of 5-26.9%) mostly involved MEN1, followed by CDC73, CASR, RET, and CDKN1B, as well as one case of VHL. Symptomatic PHP: 70-100% of all cases. Asymptomatic PHP: 60% of genetic PHP cases. Renal involvement: 10.5% of a cohort with genetic PHP, 71% of sporadic PHP cases; 50% (in a cohort with a mean age of 16.7), 29% (in a cohort with a mean age of 15.2); 0% (in infancy) to 50-62% (in teenagers). Bone anomalies: 83% of the children in one study and 62% of those in two other studies. Gastrointestinal issues: 40% of one cohort, but the data are heterogeneous. Cure rate through parathyroidectomy: 97-98%. Recurrent PHP: 2% of sporadic PHP cases and 38% of familial PHP cases. Hungry bone syndrome: maximum rate of 34-40%. Case reports identified another 7/41 subjects with the same post-parathyroidectomy condition; a potential connection with ectopic presentation or brown tumors is suggested, but there are limited data. Minimally invasive thoracoscopic approaches for ectopic tumors seemed safe. The current level of statistical evidence on pediatric PHP qualifies our study- and case-sample-based analysis (n = 48, N = 534) as one of the largest of its kind. Awareness of PHP is the key factor to benefit our young patients.

[Primary hyperparathyroidism in children]

BACKGROUND

 Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by excessive secretion of parathyroid hormone (PTH) with upper-normal or elevated blood calcium levels due to primary thyroid gland pathology. PHPT is a rare pathology in children, with a prevalence of 2-5:100,000 children according to the literature. Due to the non-specificity of clinical manifestations at onset (nausea, vomiting, abdominal pain, emotional lability), the disease may remain undiagnosed for a long time.

AIM

 To study the features of the course and molecular genetic basis of primary hyperparathyroidism in children.

MATERIALS AND METHODS

 Retrospective observational study of 49 patients diagnosed with primary hyperparathyroidism. All patients underwent a comprehensive laboratory-instrumental and molecular genetic study at the Institute of Pediatric Endocrinology, Endocrinology Research Center of Russia in the period 2014-2022.

RESULTS

 The first clinical symptoms of PHPT were noted at the age of 13.8 years [10.6; 1 5.2], among which fatigue, headaches, dyspepsia, lower limb pain, and fractures were the most common. The age of diagnosis was 15.81 years [13.1; 16.8], all children were found to have high levels of PTH, total and ionized calcium, with hypophosphatemia in 93.9% of patients (n=46) and hypercalciuria in 43% (n=21). Five out of 49 patients (10.2%) were found to have ectopy of the thyroid: 3 showed an intrathyroidal location, 2 in the mediastinal region. Molecular genetic study revealed mutations in 32.7% of patients (n=16, CI (21; 47)), mutations in MEN1 being the most frequent (n=11). Pathogenic variants in CDC73 were detected in 3 patients, RET - in 2. Among the operated 39 patients, adenoma of the thyroid was detected in 84.6% of cases (n=33), hyperplasia in 7.7% (n=3), atypical adenoma in 5.1% (n=2), carcinoma in 5.1% of cases (n=2).

CONCLUSION

 The paper presents the peculiarities of the course and the results of molecular genetic study of pediatric PHPT. This sample is the largest among those published in the Russian Federation.

Dual-phase computed tomography for localization of parathyroid lesions in children and adolescents with primary hyperparathyroidism

BACKGROUND

Childhood and adolescent primary hyperparathyroidism (PHPT) is a rare disease caused by single adenomas in 65-94% of patients. In this patient group, there is no data on computed tomography (CT) for pre-operative parathyroid localization that may facilitate focused parathyroidectomy.

METHODS

Two radiologists reviewed dual-phase (nonenhanced and arterial) CT images of twenty-three operated children and adolescents [20:single-gland disease(SGD), 3:multi-glandular disease(MGD)] with proven histopathological PHPT. Percentage arterial enhancement (PAE) was calculated as [100*{arterial-phase Hounsfield unit (HU)-nonenhanced phase HU}/nonenhanced HU] of the parathyroid lesion(s), thyroid, and lymph node.

RESULTS

Dual-phase CT lateralized 100%, localized to the correct quadrant/site 85% SGD (including 3/3 ectopic), and identified 1/3 MGD. PAE (cutoff ≥ 112.3%) was sensitive (91.3%) and specific (99.5%) in distinguishing parathyroid lesions from local mimics (P<0.001). The average effective dose was 3.16±1.01mSv, comparable to the planar/single photon emission CT (SPECT) Technetium 99m(Tc)-sestamibi and choline positron emission tomography (PET)/CT scans. Solid-cystic morphology identified in 4 patients harboring pathogenic germline variants (3:CDC73, 1:CASR) may serve as a radiological clue to molecular diagnosis. Nineteen out of 20 (95%) patients with SGD who had undergone single gland resection based on pre-operative CT findings were in remission over a median follow-up of 18 months.

CONCLUSION

As most children/adolescents with PHPT have SGD, dual-phase CT protocols which reduce the effective radiation dose with high localization sensitivity for single parathyroid lesions may be a sustainable pre-operative imaging modality in this patient group.

Clinical and genetic analysis of atypical parathyroid adenoma compared with parathyroid carcinoma and benign lesions in a Chinese cohort

CONTEXT

The malignant potential and molecular signature of atypical parathyroid adenoma (APA) remain elusive. Data from Asia are still lacking.

DESIGN AND SETTING

This was a retrospective study on a large APA cohort in a single center from mainland China.

METHODS

A total of 320 patients with primary hyperparathyroidism (PHPT), containing 79 APA, 79 Parathyroid cancer (PC) and 162 benign lesions cases, were enrolled after surgery for collection of clinical data and genetic analysis.

RESULTS

APA patients showed earlier mean onset age than benign group (46.9 ± 17.1 vs. 52.0 ± 14.3 yrs). Less bone involvement and gastrointestinal symptoms were presented in APA compared to PC (35.4% vs. 62.0%, and 17.7% vs. 41.8%), while more urolithiasis was seen in APA than in benign lesions (57.0% vs. 29.6%). The APA group had moderate hypercalcemia (mean 3.02 ± 0.44mmol/L) with elevated serum PTH (median 593.0pg/ml) and proportion of hypercalcemic crisis as 22.8%, all higher than those of benign lesions but lower than those of PC group. The recurrence/no remission rate of the APA group was significantly lower than that of the PC and similar to the benign group (5.1% vs. 31.6% vs. 3.1%). Germline CDC73 mutation was the most common molecular abnormality in both PC and APA subjects. APA patients with nonsynonymous germline variants showed earlier onset age (28.5 ± 16.9 vs. 48.1 ± 17.7 yrs) and more cases developing no remission/recurrence (25.0% vs. 0.0%).

CONCLUSIONS

Patients with APA presented clinical and biochemical characteristics much less severe than PC and resembling the benign neoplasms, with a relatively good prognosis. Germline gene variations were associated with earlier onset and probably more recurrence of PHPT in APA.

Genotype-Phenotype Correlations in Asian Indian Children and Adolescents with Primary Hyperparathyroidism

Childhood and adolescent primary hyperparathyroidism (PHPT) is a very rare disease. Data on its molecular genetics are scarce. We performed a retrospective analysis (January 2000-January 2021) to determine the deleterious germline variants and genotype-phenotype correlations in children and adolescents < 20 years diagnosed with PHPT from a single referral center. Clinical features, biochemistry, imaging, management, and genetics (clinical exome analyzed for 11 PHPT and 7 pancreatitis-associated genes, MLPA for CDC73) were recorded. Thirty-six patients (20 males; median age 17 years) were classified into those with familial and/or syndromic (F/S) or apparently sporadic (AS) presentation. Sixteen (44.4%) harbored pathogenic/likely pathogenic germline variants in PHPT-associated genes. The genetic yield in F/S group was 90% (MEN1:8/10; CDC73:1/10), and AS group was 26.9% (CDC73:4/26; CASR:3/26). F/S group had frequent asymptomatic presentation (60% vs none; P < 0.001), lower serum PTH (237.5 vs 1369.1 pg/mL; P = 0.001), and maximum parathyroid dimension (0.9 vs 2.2 cm; P = 0.01) than AS group. Among the AS group, renal involvement was higher in those with molecular diagnoses (71.4% vs 10.5%; P = 0.01). All those with novel CASR variants (including one homozygous) had hypercalciuria and histology-proven parathyroid adenoma/carcinoma. A missense CTRC VUS occurred in one patient with chronic pancreatitis. In summary, Asian Indian children and adolescents with PHPT have high genetic yield, even with apparently sporadic presentation. The phenotypic spectrum of CASR variants is expanded to include childhood/adolescent PHPT with hypercalciuria and single gland neoplasia. The proposed roles for renal involvement to predict molecular diagnosis among those with apparently sporadic presentation require further elucidation.

A novel long-range deletion spanning CDC73 and upper-stream genes discovered in a kindred of familial primary hyperparathyroidism

PURPOSE

To confirm the exact break-point of a novel long-range deletion discovered in one female parathyroid carcinoma (PC) patient who has a strong family history suggesting familial hyperparathyroidism, and to investigate the expression of parafibromin in the patient's affected lesion.

METHODS

Clinical information of one female patient as well as five of her relatives was collected. Their genomic DNA extracted from peripheral blood went through Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). After completing whole genome sequencing (WGS), clone sequencing was also performed, whose result was aligned with standard human genome database after Sanger sequencing.

RESULTS

The medical history of recurrent hypercalcemia after parathyroidectomy and histopathological investigation confirmed that the female patient was diagnosed with PC. WGS displayed a novel 130 kb long-range deletion spanning UCHL5 to CDC73 that was later confirmed by clone sequencing. MLPA showed similar results in four of her five relatives, suggesting these people to be carriers of the same long-range deletion, and three among them had a history of primary hyperparathyroidism (PHPT) ahead of the proband's first visit.

CONCLUSIONS

We discovered a novel 130 kb long-range deletion spanning CDC73 in a family of 5 persons, and the existence of the deletion was related to PHPT and PC. Our discovery validated the role of CDC73 mutation in the occurrence of PHPT and PC, which provided new information to the genetic studies of PC.

Multiple Endocrine Neoplasia in Childhood: An Update on Diagnosis, Screening, Management and Treatment

Multiple endocrine neoplasia (MEN) is a group of heterogenous syndromes characterized by the occurrence of two or more endocrine gland tumors in a patient or related individuals in the same family. They are inherited in an autosomal dominant fashion and are highly penetrant. There are three types of MEN syndromes: MEN type 1 (MEN1), MEN type 2 (MEN2), and MEN type 4 (MEN4). MEN2 is further divided into MEN2A, MEN2B (formerly known MEN3), and familial medullary thyroid carcinoma (FMTC). Although MEN syndromes are rare, it is crucial to identify individuals at risk for potentially life-threatening neoplasias. This review article provides an update on each MEN syndrome, its genetics, diagnosis, and management in children.

Changes in clinical patterns of Chinese patients with primary hyperparathyroidism in the past 12 years: a single-center experience

The clinical presentation of primary hyperparathyroidism (PHPT) differs between patients from developed and developing countries. In China, the clinical pattern has changed over the past few decades. Our aim was to elucidate general changes in the clinical characteristics of PHPT from 2010 to 2021. We enrolled 343 patients with PHPT at the Qilu Hospital of Shandong University, Jinan, China, from January 2010 to May 2021, including both surgical and non-surgical patients. Patients were divided into two subgroups, 2010-2016 (group A, n = 152) and 2017-2021 (group B, n = 191), based on the time span. We compared clinical manifestations and laboratory result data between these two groups. The mean patient age was 52.59 ± 13.55 years, and the male-to-female ratio was 1:2.54. Of the 343 patients, 183 (53.35%) had symptomatic PHPT; bone pain, urolithiasis, and fatigue were the most common symptoms. Post-operative pathology showed that 96.20% of the patients had parathyroid adenoma, whereas 2.41% had parathyroid carcinoma. Great changes occurred between 2010 and 2021; the percentage of patients with asymptomatic PHPT (aPHPT) increased from 36.18% in group A to 54.97% in group B. Moreover, patients in group B showed significantly lower serum calcium, alkaline phosphatase, parathyroid hormone, and urinary phosphate levels but higher serum 25-hydroxyvitamin D levels than those in group A. Clinical presentations in group B were also milder. In conclusion, the clinical characteristics of Chinese PHPT patients changed dramatically from 2010 to 2021, with asymptomatic PHPT (aPHPT becoming the predominant type over the last 3 years.

"Primary Hyperparathyroidism (PHPT) in Children: Two Case Reports and Review of the Literature"

Primary hyperparathyroidism (PHPT) is a rare disorder in children and adolescents. Typical biochemical features are hypercalcemia and hypophosphatemia, but the clinical features can be heterogeneous, and in some cases, symptoms are vague and nonspecific, leading to misdiagnosis or late diagnosis. Herein, we report two cases of PHPT in pediatric age with different presenting symptoms, pain in the foot, and progressive alteration of the gait in the first case and recurrent abdominal pain with emotional lability in the second. Biochemical and radiological assessment confirmed PHPT. Both cases were treated surgically as definitive treatment, but in the second case, previous medical treatment with cinacalcet, a calcimimetic agent, was required to reduce serum PTH and calcium levels. After surgery, despite conventional treatment with calcium and calcitriol, case 1 developed a hungry bone syndrome. The analysis of the MEN-1 (Multiple Endocrine Neoplasia) gene was negative in both cases. A diagnosis of PHPT should be considered when children or adolescents present bone pain with radiological imaging of osteolytic lesion and biochemical feature of hypercalcemia associated with hypophosphatemia. In PHPT, the gold standard treatment is represented by surgery followed by strict postoperative endocrine monitoring to maintain adequate homeostasis of calcium and bone metabolism.

Multiple Endocrine Neoplasia Type 1: Latest Insights

Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.

Germline GCM2 Mutation Screening in Chinese Primary Hyperparathyroidism Patients

OBJECTIVE

Glial cell missing 2 (GCM2), the critical regulator in the development of parathyroid glands, has been associated with the pathogenesis of primary hyperparathyroidism (PHPT). Relevant data in Chinese and other Asian populations are still lacking. This study aimed to screen the germline mutations of GCM2 in Chinese PHPT patients.

METHODS

A total of 232 patients diagnosed with PHPT at the Peking Union Medical College Hospital from July, 2016, to February, 2019, were screened using targeted next-generation sequencing to identify rare variants of 8 candidate genes associated with PHPT, including GCM2. Luciferase assays were performed to determine the functional impact of the GCM2 variants.

RESULTS

Four male patients were found to carry 3 rare missense variants of the GCM2 gene, including c.1162A>G (p.K388E), c.1144G>A (p.V382M), and c.1247A>G (p.Y416C). Two variants (p.K388E and p.V382M) located within a highly conserved region were associated with GCM2 transactivation function. The 2 cases carrying the p.K388E mutation had a pathology of carcinoma, and the case with the p.V382M mutation had atypical adenoma.

CONCLUSION

This study determined an overall GCM2 gain-of-function mutation frequency of 1.3% in a relatively large-sample-sized Chinese PHPT cohort and supported a higher malignant tendency in cases carrying activating GCM2 mutations. Hence, preoperative screening for these GCM2 mutations might be beneficial to treatment decisions, and longer follow-up for such patients is recommended.

Use of calcimimetics in children with normal kidney function

The calcium-sensing receptor (CaSR) plays an important role in the homeostasis of serum ionized calcium by regulating parathyroid hormone (PTH) secretion and tubular calcium handling. Calcimimetics, which act by allosteric modulation of the CaSR, mimic hypercalcemia resulting in suppression of PTH release and increase in calciuria. Mostly used in children to treat secondary hyperparathyroidism associated with advanced renal failure, we have shown that calcimimetics can also be successfully used in children with bone and mineral disorders in which elevated PTH plays a detrimental role in skeletal pathophysiology in the face of normal kidney function. The current review briefly discusses the role of the CaSR and calcimimetics in calcium homeostasis, and then addresses the potential applications of calcimimetics in children with normal kidney function with disorders in which suppression of PTH is beneficial.

Case report: incidental parathyroid adenoma in a Chinese diabetic patient with hypercalcemia and normal parathyroid hormone levels

RATIONALE

Parathyroid hormone PTH) levels are the main parameters to differentiate primary hyperparathyroidism (PHPT) from non-PTH-dependent hypercalcemia. We report a case of hypercalcemia with normal PTH levels due to a parathyroid adenoma.

PATIENT CONCERNS

A 52-year-old female patient presented with 2-year history of documented sustained high-normal serum calcium and hypercalcemia (2.51-3.03 mmol/L) with normal serum intact PTH levels (21.95-40.15 pg/ mL).

DIAGNOSES

A parathyroid tumor was localized by ultrasonography and 99mTc-sestamibi dual-phase fusion imaging with single-photon emission computed tomography/computed tomography.

INTERVENTIONS

Parathyroidectomy was performed to excise the tumor completely.

OUTCOMES

A 1.2-cm-sized parathyroid adenoma was removed surgically. The serum calcium was declined to normal level immediately after resection, as well as in 4- month follow-ups. The immunohistological diagnosis proved to be a PTH positive parathyroid adenoma.

LESSONS

In case of hypercalcemia, serum intact PTH and parathyroid imaging should be monitored to evaluate the presence of parathyroid adenoma with care because PHPT could present with inappropriate normal PTH.

When Parathyroidectomy Should Be Indicated or Postponed in Adolescents With MEN1-Related Primary Hyperparathyroidism

Multiple Endocrine Neoplasia Type 1 (MEN1) is a rare inherited endocrine tumor syndrome principally affecting parathyroid glands, neuroendocrine tissues of the gastro-entero-pancreatic and thoracic tracts, and anterior pituitary, caused by germline inactivating mutations of the MEN1 tumor suppressor gene. Primary hyperparathyroidism (PHPT) is usually the first clinical manifestation of the syndrome, normally manifesting during the third decade of life. Cases of affected children and adolescents have been described by the age of 5. Clinical characteristics and therapeutic management of MEN1 in adolescents have been described mainly by case reports. Only two studies on MEN1 patient series under the age of 22 years have recently been published. Given the scarcity of data and the lack of a consistent number of targeted studies, there are currently no specific guidelines available for children and adolescents with MEN1; diagnostic and therapeutic management is, thus, usually the same as for adult patients. Here, we report our experience with 19 adolescent MEN1 patients, developing MEN1-associated PHPT before the age of 20. Fourteen of them, manifesting hypercalcemic PHPT before the age of 20 underwent parathyroidectomy before the age of 25 to control calcemia. Parathyroid surgery restored normal calcemia in all the operated patients. No post-surgical nephrolithiasis has been reported after a mean of 12.0 ± 5.8 years of follow-up. Comparison between pre-surgical and post-surgical values of bone mineral density (BMD) in 2 patients evidenced an improvement of bone mass after parathyroid adenoma ablation. Two patients (14.28%) developed permanent post-surgical hypoparathyroidism.