Background: Inactivating mutations in the calcium sensing receptor (CASR) may result in disorders of calcium homeostasis manifesting as familial benign hypocalciuric hypercalcemia (FBHH) and neonatal severe hyperparathyroidsm (NSHPT).
Objective and hypotheses: We report two cases with NSHPT together with their treatment and long-term follow-up.
Method: Two cases were referred with severe hypercalcemia in the neonatal period. Laboratory evaluation revealed severe hypercalcemia and elevated PTH. The parents also had mild hypercalcemia.
Results: The serum calcium level did not normalize with conventional hypercalcemia treatment and there was also no response to cinacalcet in case 1. Total parathyroidectomy was performed when the patient 1 was 70 days old. Genetic analysis revealed a novel homozygous p.Arg544* mutation in the CASR gene. This patient 1 is now 1.5 years old. His height is 81 cm (25-50p) and weight is 10.7 kg (10-25p). The neuromotor development is consistent with age. Patient 2 underwent total parathyroidectomy and autoimplantation when 97 days old but the parathyroid gland implanted into the forearm was removed 27 days later because the hypercalcemia continued. Genetic evaluation revealed a novel homozygous p.Pro682Leu mutation. The case 2 is now 15 years old with a weight of 64.6 kg (1.21 SDS) and height of 165.9 cm (1.2 SDS). Neuromotor development is normal. IQ score of 60 is consistent with mild mental retardation. Normocalcemia was ensured with calcitriol. BMD evaluation revealed an L1-2 value of 1.514 g/cm2 and a Z-score of +3. No bone deformity or fracture developed during follow-up.
Conclusion: There are only a few cases diagnosed with NSHPT in the literature and very few of them have short and long-term follow-up data. There is good information on the responses to pamidronate and cinacalcet as well total parathyroidectomy with or without partial replantation that will help clinicians in future cases of NSHPT.
10 Sep 2016 - 12 Sep 2016