Is calcium signaling relevant for long bone growth?

- This case report describes for the first time a 20 year follow-up of a case of neonatal severe hyperparathyroidism (NSHPT)
- The originality is the description of the compromised growth of long bones and of the treatment with rhPTH (1-84)
- The genetic and biochemical profiles of the patient were very carefully analysed
- The results contribute to a better management of NSHPT, paving the way for the understanding growth plate cartilage development

BackgroundNeonatal severe hyperparathyroidism (NSHPT) is a rare autosomal recessive disorder of calcium homeostasis, more often induced by homozygous inactivating mutations of the calcium-sensing receptor gene. This rare syndrome can be lethal if total parathyroidectomy is not performed within the first weeks of life.Clinical reportWe report the clinical case of a male patient, son of consanguineous hypercalcemic parents, with clinical and biochemical features of NSHPT, followed until the age of 21 years. The patient underwent total parathyroidectomy, and then, due to the low compliance to calcium and calcitriol supplementation, an attempt was made with recombinant human parathyroid hormone [rhPTH (1-84)]. The patient did not reach the predicted height with an increased ratio of the upper and lower segments.ConclusionsWhile this case is unique for the length of follow-up, the continuous and detailed description of NSHPT after total parathyroidectomy in its adult phenotype, and the treatment of hypoparathyroidism with rhPTH (1-84). Following this first description of a statural defect due to shortening of long bones in NSHPT, future investigations will attempt to uncover the role of calcium signaling in growth plate cartilage in humans.