Management of familial hyperparathyroidism syndromes: MEN1, MEN2, MEN4, HPT-Jaw tumour, Familial isolated hyperparathyroidism, FHH, and neonatal severe hyperparathyroidism.

While primary hyperparathyroidism (PHPT) generally represents a common endocrine disorder, being the more frequent cause of hypercalcemia in outpatients, familial forms of PHPT (FPHPT) account for no more than 2-5% of the overall PHPT. In the last decades, many technical progresses in both molecular and biochemical-radiological evaluation have been made, and substantial advancements in understanding these disorders have been reached. Differences both in the pathogenesis and clinical presentation exist among the various hyperparathyroid syndromic forms, and, since FPHPT is frequently associated to other endocrine, proliferative and/or functional disorders, as also non-endocrine tumours, with varying clinical spectrum of occurrence in each syndrome, its early clinically detection for appropriately preventing complications (i.e. kidney and bone disorders) is strictly advised. In this review, the clinical-biochemical features and diagnostic procedures of each FPHPT form will be summarized and a general overview on surgical and pharmacological approaches to FPHPT has been also considered.

Association of Mutations in SLC12A1 Encoding the NKCC2 Cotransporter With Neonatal Primary Hyperparathyroidism.

CONTEXT: Primary hyperparathyroidism with hypercalciuria has not been described in the newborn period. OBJECTIVE: Our objectives are to identify the genetic basis for neonatal primary hyperparathyroidism in a family with 2 affected children. SUBJECTS: An African American boy presenting with mild neonatal primary hyperparathyroidism and hypercalciuria was evaluated at The Children's Hospital of Philadelphia. His older brother with neonatal primary hyperparathyroidism had died in infancy of multiple organ failure. METHODS: We collected clinical and biochemical data and performed exome sequencing analysis on DNA from the patient and his unaffected mother after negative genetic testing for known causes of primary hyperparathyroidism. RESULTS: Exome sequencing followed by Sanger sequencing disclosed 2 heterozygous mutations, c.1883C>A, p.(A628D) and c.2786_2787insC, p.(T931fsX10), in the SLC12A1 gene, which was previously implicated in antenatal type 1 Bartter syndrome. Sanger sequencing confirmed the 2 mutations in the proband and his deceased brother; both parents were heterozygous for different mutations and an unaffected sister was homozygous for wild-type alleles. CONCLUSIONS: These results demonstrate a previously unrecognized association between neonatal primary hyperparathyroidism and mutation of SLC12A1, the cause of antenatal Bartter syndrome type 1, and suggest that the loss of sodium-potassium-chloride cotransporter-2 cotransporter activity influences parathyroid gland function.

Primary hyperparathyroidism in neonates and childhood. The French experience (1984-2004).

OBJECTIVES: Primary hyperparathyroidism (HP1) in childhood is thought to be extremely rare. Its exact incidence remains unknown, as do the characteristics of HP1. A retrospective study collection was conducted on cases supplied by members of the Working Group on Calcium Metabolism throughout France over a 20-year period (1984-2004), since the availability of the intact parathormone (iPTH) radioimmunoassay. RESULTS: 55 cases were collected of which 11 were neonates. Among the 44 children and adolescents, there were 18 male and 26 female patients, ranging in age from 6 to 18 (mean 13) years. 83% were symptomatic and 43% had nephrolithiasis. Symptoms were associated with high serum calcium and inappropriate iPTH levels. Ultrasonography and technetium-labelled methoxyisobutylisonitrile scintigraphy are useful tools for the preoperative localization of adenomas, particularly in adolescents. Intraoperative iPTH assays are effective in minimizing invasive parathyroidectomy. All patients, except neonates, underwent surgery: 29 adenomas and 11 hyperplasias were found. Two multiple endocrine neoplasias (MENs) were subsequently discovered. Since the calcium-sensing receptor (CaSR) mutation was reported, the form of management in neonates has become more medical (intravenous diphosphonates) than surgical. On follow-up no recurrence was observed except for MEN. CONCLUSION: These national results reflect HP1 epidemiology. HP1 is a rare entity and appears to be a severe disease in terms of symptoms with regard to management. The use of molecular biology tests could be useful not only in neonatal cases (CaSR mutation) but also prior to surgery in children (MEN mutation).