Aetiology, Diagnosis and Surgical Treatment of Primary Hyperparathyroidism in Children: New Trends

Recurrent acute pancreatitis and primary hyperparathyroidism in patients presenting to the emergency department: Diagnostic challenges

We read the article by Karim MM et al discusses the presentation of primary hyperparathyroidism as recurrent acute pancreatitis, a rare clinical condition in pediatric patients presenting to the emergency department. As emergency medicine clinicians, we frequently encounter diverse and complex cases, and such rare conditions pose significant challenges in the diagnostic process. This article will discuss the management and diagnostic approach of such cases encountered in the emergency department.

Severe Hyperparathyroidism in a 3-year-old girl Due to Homozygous Inactivating Variant of the Calcium Sensing Receptor Gene

Homozygous inactivating pathogenic variants of calcium-sensing receptors cause severe hyperparathyroidism (HPT), typically presenting in early infancy. In the pediatric age group, HPT is uncommon and can be due to parathyroid adenoma or hyperplasia. We describe the case of a 3-year, 10-month-old girl who presented with severe HPT with symptomatic hypercalcemia, skeletal demineralization, and bone pains resulting from a homozygous missense variant p.Gly670Arg in the CaSR gene that was previously reported in association with familial hypocalciuric hypercalcemia in its heterozygous state. Parathyroidectomy with autotransplant of one-fourth of the gland in the forearm did not result in a cure even after the removal of autotransplant. In addition to controlling preoperative hypercalcemia, pamidronate helped alleviate bone pains and improve skeletal remineralization when used postoperatively for a brief period.

Adolescent primary hyperparathyroidism

Adolescent primary hyperparathyroidism (PHPT) is a rare endocrine disorder bearing distinctions from the adult form. This review examines its unique aspects, focusing on clinical presentation, genetic etiologies, genotype-phenotype correlations, and therapeutic management. Adolescent PHPT often has a genetic basis, whether familial, syndromic, or apparently sporadic, and identifying the underlying genetic cause is important for patient care. The clinical presentation is predominantly symptomatic worldwide. Unique manifestations in this age group include rickets, short stature, and slipped capital femoral epiphysis. Genotype-specific differences are evident in the adolescent PHPT characteristics. Diagnostic evaluation requires careful interpretation of biochemical and dual-energy X-ray absorptiometry findings using age and gender-specific reference ranges, with targeted screening for syndrome-associated neoplasms. Surgery remains the cornerstone of management. Current knowledge gaps in their management include treatment protocols for multiple endocrine neoplasia type 1-associated PHPT, the efficacy and safety of nonsurgical options, and long-term post-surgical outcomes.

Adolescent Hyperparathyroidism: An Updated Contemporary Surgical Experience at a Tertiary Center

INTRODUCTION

Primary hyperparathyroidism (pHPT) in children is uncommon, resulting in a paucity of data describing the disease process in this population. Herein, in an effort to bridge the information gap, we review our experience with pHPT in adolescent patients under 20 y of age at a specialized tertiary referral center.

METHODS

A retrospective chart review included all adolescent patients with pHPT, who underwent surgery at our institution between 2004 and 2023. Presenting symptoms, biochemical workup, intraoperative findings, and outcomes were collected and analyzed.

RESULTS

Forty-nine adolescent patients were included, with 45% (n = 22) being male. The median age at diagnosis was 16.6 y (14.1-20). On presentation, 71% (n = 35) were symptomatic, most commonly nephrolithiasis (35%, n = 17). The median preoperative calcium and parathyroid hormone were 12 mg/dL (11.3-12.6) and 128pg/mL (105-170.5), respectively. Focused parathyroidectomy was performed in 61% (n = 30) and four-gland exploration in 39% (n = 19) of patients. Eighty-six percent were found to have a single adenoma and 14% had multigland disease. Preoperative localization with ultrasound and Sestamibi had a sensitivity of 57% and 59%, respectively. When combining both imaging modalities, sensitivity increased to 78% (positive predictive value 91%). There were no surgical complications. At the median follow-up of 61.0 mo, 4% of patients were found to have recurrent pHPT. Younger age (OR 0.64, P = 0.038) and sporadic disease (OR 0.04, P = 0.050) had less likelihood of recurrence.

CONCLUSIONS

Most adolescent patients with pHPT present with symptoms and have single gland disease. Adolescent pHPT should be treated like adult pHPT, utilizing intraoperative PTH and two preoperative imaging modalities.

Complex Primary Hyperparathyroidism: Hereditary and Recurrent Disease

Primary hyperparathyroidism can be sporadic or part of a genetic syndrome, such as MEN1 or HPT-JT. Diagnosis of hereditary HPT requires a thorough history and physical. Parathyroidectomy is curative with greater than 95% success. However, some patients have persistent or recurrent disease requiring reoperation. Reoperative parathyroidectomy is technically challenging, and localizing the pathologic gland can difficult. Patients needing reoperation should undergo evaluation by a high-volume surgeon. Care should be taken to obtain all of the preoperative workup and operative note from the initial surgery. Radioguided parathyroidectomy can be safely and effectively performed in patients with hereditary HPT or undergoing reoperative surgery.

Atypical parathyroid adenoma with severe bone manifestations in early adolescence

This is a case of primary hyperparathyroidism in a female teenager with multiple fractures and severe bone manifestations. The histopathology revealed atypical parathyroid adenoma, an exceedingly rare form of hyperparathyroidism; its main differential diagnosis is parathyroid carcinoma, as it shares both clinical and histological characteristics with it, in addition to its still uncertain malignant potential.

Brown tumor due to primary hyperparathyroidism in a familial case: a case report

BACKGROUND

Primary hyperparathyroidism (PHPT) is an uncommon disorder characterised by hypercalcemia with an increased parathyroid hormone level. We reported a PHPT familial case with two subjects, a father and a daughter, and both of them had suffered from the brown tumor.

CASE PRESENTATION

The proband, a 43-year-old patient, developed parathyroid adenomas at the age of 15; a histologically confirmed right parathyroid adenoma was removed by parathyroidectomy; and after six months follow-up, the serum calcium level was normalised. At the age of thirty-three, a CT scan of his head and neck revealed a mass in the right maxilla, as well as PHPT (i.e., left inferior parathyroid adenoma). Then, he underwent a biopsy of an exophytic lesion in the right maxilla and was diagnosed by pathology as a brown tumor, with the serum calcium and PTH levels at 2.78 mmol/L and 221 pg/mL, respectively. Subsequently, the patient took a left inferior parathyroid microwave ablation with ultrasound guidance. After three months of follow-up, the serum calcium and PTH levels returned to normal, and the brown tumor was resolved. After three years, it mineralised as revealed in a CT scan. By the time he was 43 years old, during the 28-year follow-up period, the serum calcium and PTH levels were still within the normal range, and there was no discomfort reported. He has consistently taken calcium supplements throughout the 28 years. Since the initial diagnosis, his blood indicators of kidney function have been normal, and ultrasound showed renal calculus in the right kidney and a normal left kidney. The proband's daughter, a 15-year-old girl, experienced left upper extremity pain for ten months. CT scan revealed a mass in the distal left radius, and a giant cell tumor was suspected. A surgical internal fixation was performed, and the pathology showed a brown tumor. Laboratory tests revealed a serum parathyroid hormone (PTH) level of 1554pg/mL, calcium level of 3.14 mmol/L, phosphorus level of 0.72 mmol/L, and alkaline phosphatase level of 1892 U/L. Given the osteitic changes and elevated levels of calcium and PTH, ultrasonography was performed, after which a mass was detected measuring 19 × 9 × 7 mm mixed with solid components and cystic fluid in the right thyroid gland. The results of 99mTc-MIBI scintigraphy confirmed the abnormal accumulation of 99mTc-MIBI in the right thyroid gland but not seen in the bilateral parathyroid glands. The patient underwent thyroidectomy, and the postoperative pathology report indicated an intra-thyroid ectopic parathyroid adenoma. The serum calcium and PTH levels became normal at 4 h after surgery. One to three months after operation, the serum calcium level was low, while the serum PTH level was high. Then, the patient was advised to take calcium supplements. Until the sixth month after the operation, the serum calcium level and serum PTH level returned to normal, and the bone pain was relieved. The patient's blood tests for kidney function remained normal. There was no evidence of bilateral kidney disease (such as nephrolithiasis or nephrocalcinosis) detected by ultrasound scan. There were several similarities in the state of illness between these two subjects. Both the father and the daughter developed parathyroid adenomas at the age of 15, and there was no lesion in other endocrine glands. And genetic testing revealed mutations in the CDC73 genes in both father and daughter. On the other hand, there were also a few differences. The father's first signs of brown tumor were in the right maxilla, while the daughter's appeared in the distal left radius. The father presented pathological changes in the left and right parathyroid glands, whereas the daughter presented with an ectopic parathyroid adenoma in the right thyroid gland.

CONCLUSION

We report a familial case in which father and daughter were diagnosed to have brown tumors due to parathyroid adenoma and ectopic parathyroid adenoma, and genetic testing revealed CDC73 gene mutations in both. Therefore, in the diagnostic and differential process of young patients having bone disease, clinicians should not only focus on the clinical manifestations of the skeleton, but also implement a comprehensive analysis of systemic symptoms, considering the possibility that the patient has familial PHPT.

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.

Pitfalls in the Diagnosis of Primary Hyperparathyroidism in a Sudanese Adolescent Boy; a case disguised as rickets

BACKGROUND

Juvenile primary hyperparathyroidism (PHPT) is a rare endocrine disease. Its diagnosis might be masked by clinical, biochemical, and radiological features of rickets.

CASE PRESENTATION

A 12-year-old Sudanese boy presented with progressive lower limbs deformity and difficulty in walking for six months. It was associated with fatigability, poor appetite, and generalized bone pain. On examination, he was thin, disproportionately short and pubertal, and had bilateral genu valgum deformity. X-rays showed osteopenia and signs of rickets. Biochemical workup revealed mildly elevated serum calcium, low phosphate, high alkaline phosphatase, and high parathyroid hormone with low 25-hydroxy vitamin D₃. Celiac screening, liver function test and renal profile were normal. Serum calcium rose dramatically after vitamin D therapy. Genetic testing was negative for CYP2R1 and MEN1 genes. Ultrasound neck showed left inferior parathyroid adenoma which was surgically excised. Histopathology confirmed the diagnosis of parathyroid adenoma. Postoperatively, he had hypocalcemia which was treated with calcium and alfacalcidol. Corrective surgery is planned for the genu valgum deformity which markedly improved after parathyroidectomy.

CONCLUSION

Although PHPT is extremely rare in the young population, it should be considered in patients with rickets and elevated serum calcium at baseline or after initiating vitamin D therapy.

Features of the diagnosis of primary hyperparathyroidism in children

Background. Primary hyperparathyroidism (PHPT) is a rare pathology in pediatric and adolescent patients. Collection, analysis and generalization of the literature data and experience of the leading clinics allow to develop unified, statistically substantiated approaches to diagnostics and surgical treatment of this group of patients.

Material and methods. The article presents a retrospective analysis of 17 cases of PHPT in children and adolescents aged from 6 to 18 years operated on in the department of Surgery of St.-Petersburg State Pediatric Medical University in the period from 1973 till 2021. Among those operated there were 10 girls and 7 boys, the M:F ratio was 1:1.4. The mean age of the patients was 12,9±0,71 years.

Results and discussion. The main criteria of the disease diagnosis were elevated blood calcium and parathormone levels, excessive urinary calcium secretion. Manifest forms of the disease were diagnosed in 10 (58,8%) of 17 children. In 3 (17,6%) cases the parathyroid neoplasms were accompanied neither by clinical, nor laboratory manifestations of the disease and were regarded as incidentalomas. Another 4 (23.5%) patients had only laboratory changes (hypercalcemia and hyperparathyrinaemia) that manifested themselves preoperatively. These observations were referred to the asymptomatic form of PHPT.

In 7 (41.2%) cases parathyroid adenomas were found and removed during surgeries for various thyroid diseases (thyroid cancer in 5 cases, diffuse toxic goiter in 1 case). An incidental finding of parathyroid adenoma was during prophylactic thyroidectomy for Sipple syndrome.

A radioisotope method proved to be the most informative way to localize parathyroid tumors.

Conclusion. The diagnosis of the disease in manifest sporadic cases does not differ from that in adults. Genetic study is indicated in the presence of a family history of multiple involvement of the parathyroid glands. Surgical treatment with removal of parathyroid tumor is the main method, which allows to achieve complete recovery. 

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.

Off-label use of cinacalcet in pediatric primary hyperparathyroidism: A French multicenter experience

BACKGROUND

Cinacalcet is a calcimimetic approved in adults with primary hyperparathyroidism (PHPT). Few cases reports described its use in pediatric HPT, with challenges related to the risk of hypocalcemia, increased QT interval and drug interactions. In this study, we report the French experience in this setting.

METHODS

We retrospectively analyzed data from 18 pediatric patients from 7 tertiary centers who received cinacalcet for PHPT. The results are presented as median (interquartile range).

RESULTS

At a median age of 10.8 (2.0-14.4) years, 18 patients received cinacalcet for primary HPT (N = 13 inactive CASR mutation, N = 1 CDC73 mutation, N = 1 multiple endocrine neoplasia type 1, N=3 unknown etiology). Cinacalcet was introduced at an estimated glomerular filtration rate (eGFR) of 120 (111-130) mL/min/1.73 m², plasma calcium of 3.04 (2.96-3.14) mmol/L, plasma phosphate of 1.1 (1.0-1.3) mmol/L, age-standardized (z score) phosphate of -3.0 (-3.5;-1.9), total ALP of 212 (164-245) UI/L, 25-OHD of 37 (20-46) ng/L, age-standardized (z score) ALP of -2.4 (-3.7;-1.4), PTH of 75 (59-123) ng/L corresponding to 1.2 (1.0-2.3)-time the upper limit for normal (ULN). The starting daily dose of cinacalcet was 0.7 (0.6-1.0) mg/kg, with a maximum dose of 1.0 (0.9-1.4) mg/kg per day. With a follow-up of 2.2 (1.3-4.3) years on cinacalcet therapy, PTH and calcium significantly decreased to 37 (34-54) ng/L, corresponding to 0.8 (0.5-0.8) ULN (p = 0.01), and 2.66 (2.55-2.90) mmol/L (p = 0.002), respectively. In contrast, eGFR, 25-OHD, ALP and phosphate and urinary calcium levels remained stable. Nephrocalcinosis was not reported but one patient displayed nephrolithiasis. Cinacalcet was progressively withdrawn in three patients; no side effects were reported.

CONCLUSIONS

Cinacalcet in pediatric HPT can control hypercalcemia and PTH without significant side effects.

Hereditary Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a commonly encountered clinical problem and occurs as part of an inherited disorder in ∼10% of patients. Several features may alert the clinician to the possibility of a hereditary PHPT disorder (eg, young age of disease onset) whilst establishing any relevant family history is essential to the clinical evaluation and will help inform the diagnosis. Genetic testing should be offered to patients at risk of a hereditary PHPT disorder, as this may improve management and allow the identification and investigation of other family members who may also be at risk of disease.

Successful Use of Denosumab for Life-Threatening Hypercalcemia in a Pediatric Patient with Primary Hyperparathyroidism

INTRODUCTION

Primary hyperparathyroidism (PHPT) is rare and usually symptomatic in children. There is no approved medication to lower serum calcium levels in this patient group. Denosumab is used in adult patients with osteoporosis and hyperparathyroidism. To our knowledge, only 1 case of denosumab treatment in a child with severe PHPT has been reported to date.

CASE PRESENTATION

A 16-year-old female was referred to our clinic with symptoms including pathologic fractures, nausea, emesis, and progressive weight loss. At admission, her serum total calcium was 4.17 mmol/L (reference range 2.15-2.55), parathyroid hormone 2,151 pg/mL (15-65), and phosphate 1.07 mmol/L (1.45-1.78). Due to potentially life-threatening hypercalcemia, denosumab 60 mg subcutaneously was administered after obtaining informed consent. Serum calcium levels were reduced within 12 h of injection and the patient's condition rapidly improved, which allowed genetic testing to be done prior to surgery. A heterozygous mutation in the CDC73 gene was revealed, and a parathyroidectomy was performed on day 22 after denosumab administration. Morphological examination revealed solitary parathyroid adenoma. After surgery, hypocalcemia developed requiring high doses of alfacalcidol and calcium supplements.

CONCLUSION

Our case supports the previous observations in adults that denosumab can be safely and effectively used as a preoperative treatment in patients with PHPT and severe hypercalcemia and shows that it may be used in pediatric patients.

Ectopic Parathyroid Adenoma in an 11-Year-Old Girl: Case Report and Literature Review

Objective

Primary hyperparathyroidism secondary to an ectopic parathyroid adenoma is rare among children and adolescents.

Methods

We describe the case of an 11-year-old girl with incidentally diagnosed primary hyperparathyroidism secondary to an intrathymic parathyroid adenoma and performed a review of the related literature.

Results

^99mTechnetium sestamibi single-photon emission computerized tomography/computed tomography and 4-dimensional computed tomography confirmed the ectopic location of the adenoma. The patient underwent thoracoscopic thymectomy and remained normocalcemic with elevated parathyroid hormone showing a downward trend. Parathyroid hormone normalized 18 months after successful parathyroidectomy.

Conclusion

We review the case of a rare mediastinal parathyroid adenoma in a pediatric patient and summarize the epidemiologic profile, diagnosis, and management of similar pediatric cases.

"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.

Bilateral Genu Valgum in an Adolescent with Primary Hyperparathyroidism: A Case Report and Review of Literature

Primary hyperparathyroidism in children and adolescents is rare and often symptomatic at presentation. A 15-year-old bo presented with bilateral genu valgum for two years. Biochemical results were consistent with primary hyperparathyroidism Calcium levels normalized two months after removal of a left inferior parathyroid adenoma.

A Familial Case of a Whole Germline CDC73 Deletion Discordant for Primary Hyperparathyroidism

INTRODUCTION

Primary hyperparathyroidism (PHPT) occurs as part of familial syndromes, including CDC73-related disorders caused by germline pathogenic variants of the CDC73 gene, particularly in early adulthood. Herein, we report a familial case of a whole germline CDC73 deletion discordant for PHPT.

CASE DESCRIPTION

A 15-year-old boy was admitted to our hospital because of persistent nausea and vomiting. Laboratory tests showed hypercalcemia (13.6 mg/dL), hypophosphatemia (2.4 mg/dL), and elevated intact PTH level (149 pg/mL). Imaging studies showed an enlarged single parathyroid gland. Thus, the diagnosis of PHPT was made. Microarray analysis of peripheral blood DNA showed a 3.4-Mb heterozygous deletion of 1q31 encompassing 11 genes, including CDC73. Total thyroidectomy/parathyroidectomy was performed; histology was compatible with parathyroid adenoma without any evidence of malignancy. DNA sequencing of the removed adenoma confirmed a hemizygous nonsense variant in the CDC73 gene in a mosaic manner, which was potentially involved in parathyroid tumorigenesis as the "second hit." Importantly, the same deletion was identified in his 52-year-old father who had an unremarkable medical history.

CONCLUSIONS

These data clearly demonstrate the Knudson two-hit theory from a molecular viewpoint. Phenotypic variability and incomplete penetrance of CDC73-related disorders, even if caused by a gross deletion, should be noted in a clinical setting.

Clinical genetic testing in endocrinology: Current concepts and contemporary challenges

Recent advances in DNA sequencing technology have led to an unprecedented period of disease-gene discovery offering many new opportunities for genetic testing in the clinical setting. Endocrinology has seen a rapid expansion in the taxonomy of monogenic disorders, which can be detected by an expanding portfolio of genetic tests in both diagnostic and predictive settings. Successful testing relies on many factors including the ability to identify those at increased risk of genetic disease in the busy clinic as well as a working knowledge of the various testing platforms and their limitations. The clinical utility of a given test is dependent upon many factors, which include the reliability of the genetic testing platform, the accuracy of the test result interpretation and knowledge of disease penetrance and expression. The increasing adoption of "high-content" genetic testing based on next-generation sequencing (NGS) to diagnose hereditary endocrine disorders brings a number of challenges including the potential for uncertain test results and/or genetic findings unrelated to the indication for testing. Therefore, it is increasingly important that the clinician is aware of the current evolution in genetic testing, and understands the different settings in which it may be employed. This review provides an overview of the genetic testing workflow, focusing on each of the major components required for successful testing in adult and paediatric endocrine settings. In addition, the challenges of variant interpretation are highlighted, as are issues related to informed consent, prenatal diagnosis and predictive testing. Finally, the future directions of genetic testing relevant to endocrinology are discussed.

Primary hyperparathyroidism in young patients in Russia: high frequency of hyperparathyroidism-jaw tumor syndrome

BACKGROUND

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.

OBJECTIVE

To identify and describe hereditary forms of PHPT in patients with manifestation of the disease under 40 years of age.

DESIGN

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Hypercalcemic Disorders in Children

Hypercalcemia is defined as a serum calcium concentration that is greater than two standard deviations above the normal mean, which in children may vary with age and sex, reflecting changes in the normal physiology at each developmental stage. Hypercalcemic disorders in children may present with hypotonia, poor feeding, vomiting, constipation, abdominal pain, lethargy, polyuria, dehydration, failure to thrive, and seizures. In severe cases renal failure, pancreatitis and reduced consciousness may also occur and older children and adolescents may present with psychiatric symptoms. The causes of hypercalcemia in children can be classified as parathyroid hormone (PTH)-dependent or PTH-independent, and may be congenital or acquired. PTH-independent hypercalcemia, ie, hypercalcemia associated with a suppressed PTH, is commoner in children than PTH-dependent hypercalcemia. Acquired causes of PTH-independent hypercalcemia in children include hypervitaminosis; granulomatous disorders, and endocrinopathies. Congenital syndromes associated with PTH-independent hypercalcemia include idiopathic infantile hypercalcemia (IIH), William's syndrome, and inborn errors of metabolism. PTH-dependent hypercalcemia is usually caused by parathyroid tumors, which may give rise to primary hyperparathyroidism (PHPT) or tertiary hyperparathyroidism, which usually arises in association with chronic renal failure and in the treatment of hypophosphatemic rickets. Acquired causes of PTH-dependent hypercalcemia in neonates include maternal hypocalcemia and extracorporeal membrane oxygenation. PHPT usually occurs as an isolated nonsyndromic and nonhereditary endocrinopathy, but may also occur as a hereditary hypercalcemic disorder such as familial hypocalciuric hypercalcemia, neonatal severe primary hyperparathyroidism, and familial isolated primary hyperparathyroidism, and less commonly, as part of inherited complex syndromic disorders such as multiple endocrine neoplasia (MEN). Advances in identifying the genetic causes have resulted in increased understanding of the underlying biological pathways and improvements in diagnosis. The management of symptomatic hypercalcemia includes interventions such as fluids, antiresorptive medications, and parathyroid surgery. This article presents a clinical, biochemical, and genetic approach to investigating the causes of pediatric hypercalcemia. © 2017 American Society for Bone and Mineral Research.

Case report: rare skeletal manifestations in a child with primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (PHPT) is uncommon among children with an incidence of 1:300,000. This diagnosis is often missed in children in contrast to adults where it is detected at a pre symptomatic stage due to routine blood investigations. Etiology of PHPT can be due to adenoma, hyperplasia or rarely carcinoma.

CASE PRESENTATION

A 12 year old Sri Lankan girl presented with progressive difficulty in walking since 1 year. On examination she had bilateral genu valgum. Skeletal survey revealed valgus deformity of knee joints, bilateral subluxation of upper femoral epiphysis(SUFE), epiphyseal displacement of bilateral humeri, rugger jersey spine and subperiosteal bone resorptions in lateral aspects of 2nd and 3rd middle phalanges. There were no radiological manifestations of rickets. Metabolic profile revealed hypercalcemia with hypophosphatemia. Intact parathyroid hormone levels were elevated at 790 pg/ml. Vitamin D levels were deficient. She had low bone mineral density with Z score of -3.4. Vitamin D supplementation resulted in worsening of hypercalcemia without reduction in PTH levels. Tc 99 Sestamibi uptake scan showed abnormal tracer retention in left inferior pole of thyroid. A large parathyroid gland was removed with histology favoring parathyroid adenoma. Post operatively she developed hypocalcemia. Bilateral osteotomy was done for SUFE and further surgeries for correction of limb deformities planned.

CONCLUSION

PHPT in children is usually diagnosed late when irreversible organ damage has occurred. Children can present with non specific symptoms involving gastrointestinal, musculoskeletal, renal and neurological systems. PHPT can cause disarray in bone and epiphysis in children during pubertal growth spurt. Genu valgum and SUFE are rare skeletal manifestations in PHPT and only 10 cases of genu valgum and 9 cases of SUFE have been reported up to now. So far no cases have been reported on epiphyseal displacement of humeri. Awareness regarding the occurrence of these rare skeletal manifestations especially during puberty is important for early diagnosis to prevent irreversible outcomes.

Giant parathyroid adenoma associated with severe hypercalcemia in an adolescent patient

BACKGROUND

The objective of this study is to bring attention to the importance of differential diagnosis in adolescent patients with skeletal involvement and hypercalcemia.

CASE

A 17-year-old male patient with a complaint of severe leg pain was admitted to our hospital. Seven months before he had a fracture of his distal humerus after falling on to his left shoulder and was treated conservatively. Five months previously, he had a rupture of his quadriceps tendon. Magnetic resonance imaging (MRI) was performed for the quadriceps tendon rupture and was evaluated as polyostotic fibrous dysplasia (PFD). Doctors decided to operate for the ruptured tendon but they detected severe hypercalcemia in the pre-operative blood tests and noticed that the main disease was primary hyper-parathyroidisim (PHPT) which was caused by a giant parathyroid adenoma. Conclusions Giant parathyroid adenoma can present in adolescent patients with multiple bone lesions and severe hypercalcemia. PHPT should be considered in the differential diagnosis of pathological bone fractures and benign bone tumors in every age. This may prevent patients from miss or delayed diagnosis of PHPT.

Primary hyperparathyroidism may masquerade as rickets-osteomalacia in vitamin D replete children

Primary hyperparathyroidism, typically a disease of the middle aged and the old, is less commonly seen in children. In children the disease has a bimodal age distribution with calcium sensing receptor mutation presenting in infancy as hypercalcemic crises and parathyroid adenoma or hyperplasia presenting later in childhood with bone disease. The childhood parathyroid adenomas are often familial with multiglandular disease and manifest with severe bone disease unlike adults. We report a series of four male patients with juvenile primary hyperparathyroidism, three of whom presented with bone disease masquerading as rickets-osteomalacia. One patient had asymptomatic hypercalcemia with short stature. Parathyroid adenoma was detected in all the four cases and all of them underwent resection of parathyroid adenomas confirmed on histopathology. Post-surgery all the cases had initial hypocalcaemia followed by normocalcemia. One case developed pancreatitis after surgery even after achieving normocalcemia. We conclude that parathyroid adenomas, although uncommon in children, are an important cause of skeletal disease that may initially be confused with hypovitaminosis D.