Prevalence of Pseudohypoparathyroidism and Nonsurgical Hypoparathyroidism in Japan in 2017: A Nationwide Survey

Pseudohypoparathyroidism type 1B with involuntary movements: a case report and literature review

Pseudohypoparathyroidism (PHP) is a rare disorder characterized by convulsions, tetany, and sensory abnormalities caused by hypocalcemia due to parathyroid hormone (PTH) resistance. Only few patients present with involuntary movements. We report the case of a 7-yr-old girl with PHP and involuntary movements triggered by running. Initially, she was suspected of having paroxysmal kinesigenic dyskinesia and was treated with carbamazepine (CBZ). Involuntary movements were reduced. However, 2 months post-treatment, she experienced convulsions during a fever. Blood tests and brain computed tomography revealed hypocalcemia, hyperphosphatemia, elevated intact PTH, and calcifications in the frontal cortex and basal ganglia. The patient showed no features of Albright's hereditary osteodystrophy. The involuntary movements disappeared after the discontinuation of CBZ and initiation of calcium and active vitamin D preparations. Methylation-specific multiplex ligation-dependent probe amplification for the GNAS region and microsatellite analysis of chromosome 20 led to the diagnosis of PHP1B caused by epimutation. In 15 reported cases, with or without intracranial calcification, PHP-associated involuntary movements disappeared or became less severe with treatment for hypocalcemia; in eight of 11 cases, they were triggered by exercise or movement. PHP-associated hypocalcemia can trigger exercise-induced involuntary movements owing to lowered serum ionized calcium levels. In such patients, early blood tests are vital for the differential diagnosis of PHP.

GNAS locus: bone related diseases and mouse models

GNASis a complex locus characterized by multiple transcripts and an imprinting effect. It orchestrates a variety of physiological processes via numerous signaling pathways. Human diseases associated with the GNAS gene encompass fibrous dysplasia (FD), Albright's Hereditary Osteodystrophy (AHO), parathyroid hormone(PTH) resistance, and Progressive Osseous Heteroplasia (POH), among others. To facilitate the study of the GNAS locus and its associated diseases, researchers have developed a range of mouse models. In this review, we will systematically explore the GNAS locus, its related signaling pathways, the bone diseases associated with it, and the mouse models pertinent to these bone diseases.

Pseudohypoparathyroidism during pregnancy and the postpartum period: A case series of five patients

OBJECTIVES

Pseudohypoparathyroidism (PHP) is a rare disease, especially when combined with pregnancy. We aimed to explore the changes in serum calcium/parathyroid hormone (PTH) level and medical treatment in a case series of PHP during pregnancy and the postpartum period.

METHODS

A total of five PHP patients with six pregnancies were enrolled. The classification of PHP was based on (epi)genetic analysis. Clinical characteristics, biochemical indices, and treatment strategies before, during, and after pregnancy were retrospectively collected.

RESULTS

All patients received calcium and vitamin D agents with nearly normal serum calcium before pregnancy except patient 2 who was found hypocalcemic during gestation. All patients chose Cesarean section, and one suffered preterm delivery due to oligoamnios. The neonatal birth weight ranged from 2,250 to 4,300 g, and all neonates were free of hypocalcemia-related symptoms. The change in calcium metabolism was inconsistent including stable, improved, or worsened during pregnancy. Serum PTH level remained low in the first two trimesters in patients with stable and improved conditions while increased in the last two trimesters in patients with a worsened condition. Serum calcium changed inconsistently while PTH increased consistently during lactation. For patients who did not breastfeed, calcium homeostasis improved after delivery.

CONCLUSION

Calcium homeostasis and medicine dosage changed differently in PHP patients during pregnancy and lactation. However, most patients had good pregnancy outcomes. Serum PTH levels might predict changes in calcium metabolism during pregnancy.