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Open access

Marisa M Fisher, Susanne M Cabrera and Erik A Imel

Summary

Neonatal severe hyperparathyroidism (NSHPT) is a rare disorder caused by inactivating calcium-sensing receptor (CASR) mutations that result in life-threatening hypercalcemia and metabolic bone disease. Until recently, therapy has been surgical parathyroidectomy. Three previous case reports have shown successful medical management of NSHPT with cinacalcet. Here we present the detailed description of two unrelated patients with NSHPT due to heterozygous R185Q CASR mutations. Patient 1 was diagnosed at 11 months of age and had developmental delays, dysphagia, bell-shaped chest, and periosteal bone reactions. Patient 2 was diagnosed at 1 month of age and had failure to thrive, osteopenia, and multiple rib fractures. Cinacalcet was initiated at 13 months of age in patient 1, and at 4 months of age in patient 2. We have successfully normalized their parathyroid hormone and alkaline phosphatase levels. Despite the continuance of mild hypercalcemia (11–12 mg/dl), both patients showed no hypercalcemic symptoms. Importantly, patient 1 had improved neurodevelopment and patient 2 never experienced any developmental delays after starting cinacalcet. Neither experienced fractures after starting cinacalcet. Both have been successfully managed long-term without any significant adverse events. These cases expand the current literature of cinacalcet use in NSHPT to five successful reported cases. We propose that cinacalcet may be considered as an option for treating the severe hypercalcemia and metabolic bone disease found in infants and children with inactivating CASR disorders.

Learning points

  • NSHPT due to mutations in the CASR gene occurs with hypercalcemia and metabolic bone disease, but not always with severe critical illness in infancy.

  • NSHPT should be considered in the differential diagnosis for a newborn with a bell-shaped chest, osteopenia, and periosteal reactions.

  • Neurodevelopmental consequences may occur in children with hypercalcemia and may improve during treatment.

  • Calcimimetics can be used to successfully treat the pathophysiology of NSHPT directly to control serum calcium levels.

Open access

Maria P Yavropoulou, Nikolina Gerothanasi, Athanasios Frydas, Evangelia Triantafyllou, Chris Poulios, Prodromos Hytiroglou, Panagiotis Apostolou, Ioannis Papasotiriou, Symeon Tournis, Isaak Kesisoglou and John G Yovos

Summary

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused primarily by benign mesenchymal tumors. These tumors typically follow a benign clinical course and local recurrence occurs in <5% of cases. We investigated a 49-year-old man with a recurrent mesenchymal phosphaturic tumor showing no signs of malignancy. The patient suffered from chronic muscle weakness, myalgia and cramps. His medical record included the diagnosis of oncogenic osteomalacia, for which he was submitted to tumor resection in the left leg three times before. Laboratory examination showed hypophosphatemia, hyperphosphaturia and an elevated serum FGF23 level. A radical surgical approach (amputation) was advised, however, complete biochemical and clinical remission was not reached. Molecular analysis of the tumor cells demonstrated overexpression of growth factor receptors implicated in tumor angiogenesis and metastatic potential (platelet derived growth factor type A (PDGFRA), PDGFRB and vascular endothelial growth factor receptor) together with increased expression of FGF23, x-linked-phosphate-regulating endopeptidase and KLOTHO. TIO is usually associated with benign phosphauturic tumors and, when identified, resection of the tumor leads to complete remission in the majority of cases. The underlying pathophysiology of recurrences in these tumors is not known. This is the first report showing increased expression of growth factor receptors in a locally aggressive but histopathologically benign phosphaturic mesenchymal tumor.

Learning points

  • TIO is usually associated with benign soft tissue or bone neoplasms of mesenchymal origin.

  • These tumors typically follow a benign clinical course and even in the rare malignant cases local recurrence occurs in <5%.

  • Successful identification and removal of the tumor leads to full recovery in the majority of cases.

Open access

Shweta Birla, Viveka P Jyotsna, Rajiv Singla, Madhavi Tripathi and Arundhati Sharma

Summary

Multiple endocrine neoplasia type 1 (MEN-1) is a rare autosomal-dominant disease characterized by tumors in endocrine and/or non endocrine organs due to mutations in MEN1 encoding a nuclear scaffold protein‘menin’ involved in regulation of different cellular activities. We report a novel 14 bp MEN1 deletion mutation in a 35-year-old female with history of recurrent epigastric pain, vomiting, loose stools and weight loss. On evaluation she was diagnosed to have multifocal gastro-duodenal gastrinoma with paraduodenal lymph nodes and solitary liver metastasis. She was also found to have primary hyperparathyroidism with bilateral inferior parathyroid adenoma. Pancreatico-duodenectomy with truncalvagotomy was performed. Four months later, radiofrequency ablation (RFA) of segment 4 of the liver was done followed by three and a half parathyroidectomy. MEN1 screening was carried out for the patient and her family members. MEN-1 sequencing in the patient revealed a heterozygous 14 bp exon 8 deletion. Evaluation for pathogenicity and protein structure prediction showed that the mutation led to a frameshift thereby causing premature termination resulting in a truncated protein. To conclude, a novel pathogenic MEN1 deletion mutation affecting its function was identified in a patient with hyperparathyroidism and gastrinoma. The report highlights the clinical consequences of the novel mutation and its impact on the structure and function of the protein. It also provides evidence for co-existence of pancreatic and duodenal gastrinomas in MEN1 syndrome. MEN1 testing provides important clues regarding etiology and therefore should be essentially undertaken in asymptomatic first degree relatives who could be potential carriers of the disease.

Learning points

  • Identification of a novel pathogenic MEN1 deletion mutation.

  • MEN1 mutation screening in patients with pituitary, parathyroid and pancreatic tumors, and their first degree relatives gives important clues about the etiology.

  • Pancreatic and duodenal gastrinomas may co-exist simultaneously in MEN1 syndrome.

Open access

Katsumi Taki, Takahiko Kogai, Junko Sakumoto, Takashi Namatame and Akira Hishinuma

Summary

A de novo heterozygous inactivating mutation of calcium-sensing receptor (CASR) gene typically causes neonatal hyperparathyroidism (NHPT) with moderate hypercalcemia and hyperparathyroid bone disease. We present a case of asymptomatic hypocalciuric hypercalcemia with a de novo heterozygous mutation in CASR, S591C, which is primarily reported to be responsible for NHPT. A 54-year-old female was referred for investigation of asymptomatic hypercalcemia that was initially found in the 1980s but without a history of bone disease during the perinatal period. She had moderate hypercalcemia (12.4 mg/dl) and relative hypocalciuria (fractional extraction of calcium 1.07%) but normal intact parathyroid hormone and serum 1,25-dihydroxyvitamin D3. Pedigree analysis revealed that she carried a de novo heterozygous mutation of S591C, which she transmitted to an affected child with moderate hypercalcemia but not to other children, who had normal serum calcium levels. A de novo heterozygous CASR mutation that is responsible for NHPT may also present in individuals with asymptomatic hypocalciuric hypercalcemia. Caution is required when predicting course and outcome in a pedigree with CASR mutation, as well as incidental hypercalcemia, because of its variable phenotypes.

Learning points

  • The phenotype and severity of CASR mutations are thought to be dependent on genotypes.

  • We report an asymptomatic case of the de novo heterozygous S591C mutation in CASR, which has previously been reported as a responsible mutation of NHPT with bone diseases.

  • Variable phenotypes of CASR raise a cautionary note about predicting outcome by genotyping in a pedigree with CASR mutation.

Open access

E Castellano, M Pellegrino, R Attanasio, V Guarnieri, A Maffè and G Borretta

Summary

We report the association of primary hyperparathyroidism (PHPT) and Klinefelter's syndrome (KS) in a 22-year-old male complaining of worsening fatigue. PHPT was asymptomatic at the diagnosis, but the patient had worsening hypercalcemia and osteoporosis, and developed acute renal colic. He then underwent parathyroidectomy with resection of a single adenoma and normalization of calcium and parathyroid hormone levels. Clinical and therapeutic implications of this rare association are discussed.

Learning points

  • The coexistence of KS and PHPT is very uncommon.

  • Patients with mild PHPT often have nonspecific symptoms that may be confused and superimposed with those of hypogonadism.

  • KS patients, especially when young and already osteoporotic at diagnosis, should be screened for other causes of secondary osteoporosis, in particular PHPT.

Open access

Kirun Gunganah, Ashley Grossman and Maralyn Druce

Summary

A 22-year-old female student presented with a history of recurrent pancreatitis. The commonest causes of pancreatitis, including drugs, gallstones, corticosteroids, excess alcohol and hypertriglyceridaemia, were excluded. She was found to have an elevated serum calcium level that was considered to be the cause of her pancreatitis, with a detectable serum parathyroid hormone (PTH). An initial diagnosis of primary hyperparathyroidism was made. However, two neck explorations failed to reveal a parathyroid adenoma. She was referred to our unit three years later as her episodes of pancreatitis were becoming more frequent and her calcium level remained persistently elevated. Her investigations were as follows: elevated adjusted calcium level of 2.79 mmol/l (2.2–2.58), PTH level of 4.2 pmol/l (0.6–6.0), low 24 h urine calcium of 0.3 mmol/l and a urine calcium:creatinine ratio of <0.003. A clinical diagnosis of familial hypocalciuric hypercalcaemia (FHH) was made and confirmed on genetic testing that showed a c.1703 G>A mutation in the calcium-sensing receptor gene. Although the hypercalcaemia of FHH is usually without sequelae due to the generalised changes in calcium sensing, in the presence of this complication she was started on cinacalcet 30 mg daily. She had one further episode of pancreatitis with calcium levels ranging between 2.53 and 2.66 mmol/l. Her cinacalcet was gradually increased to 30 mg three times daily, maintaining her calcium levels in the range of 2.15–2.20 mmol/l. She has not had a further episode of pancreatitis for more than 2 years.

FHH is usually a benign condition with minimal complications from hypercalcaemia. Pancreatitis has been reported rarely, and no clear management strategy has been defined in these cases. Cinacalcet was successfully used in treating recurrent pancreatitis in a patient with FHH by maintaining calcium levels in the lower part of the reference range. Whether or not this is an effective long-term treatment remains yet to be seen.

Learning points

  • FHH is an important differential diagnosis for hypercalcaemia.

  • FHH can rarely cause pancreatitis.

  • No clear strategy is available to help in the management of patients with pancreatitis due to FHH.

  • Cinacalcet was effective in lowering serum calcium levels and reducing the frequency of pancreatitis in our patient with FHH.