Clinical Trial: Hypoparathyroidism in Denmark

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Hypoparathyroidism, Autosomal Dominant Hypocalcaemia and Pseudohypoparathyroidism in Denmark - Epidemiology, Causes, Symptoms and Prognoses

Brief Summary: The purpose of this study is to identify the number of persons in Denmark with the diagnose hypoparathyroidism, autosomal dominant hypocalcaemia or pseudohypoparathyroidism. Also the investigators want to identify the causes and symptoms of these patients and their prognosis.

Detailed Summary:

Hypoparathyroidism (HypoPT) is a relatively rare disease, where the level of parathyroid hormone (parat hormone [PTH]) cannot maintain a physiologically sufficient concentration of plasma calcium (P-Ca). This may be due to neck surgery (most frequently), congenital HypoPT, auto-immune destruction of the parathyroid gland, peripheral resistance to PTH, pseudoHypoPT or magnesium deficiency, by which PTH cannot be released from parathyroid gland.

Low plasma levels of P-Ca are registered by the calcium-sensing-receptors (CaSR) located e.g. in the gld. Parathyroid cell membranes and in the renal tubules, by which the flow of PTH into plasma increases, with normalization of P-Ca and decreasing P-phosphate to follow. By lack of PTH the renal synthesis of 1,25-dihydroxycholecalciferol is dismissed, with decreased bone turnover as a consequence.

Congenital causes of HypoPT are very rare and seen either sporadic or hereditary. The hereditary forms are more frequent in some areas of the world: founder-effect and familial marriages. Autoimmune HypoPT caused by mutations in the AIRE gene results in lack of negative selection of the T-cells in thymus. Autosomal dominant hypocalcaemia is caused by gain-of-function mutations in the G-protein receptor CaRS in the main cells in the parathyroid gland and kidney tubules. PseudoHypoPT is due to resistance in the target organs, despite high concentrations of PTH. The symptoms are shown by Albrights's hereditary osteodystrophy, (AOH), (maternal allel). PseudopseudoHypoPT is characterized by AOH, but without the typical biochemical findings (paternal allel).

The clinical manifestations of HypoPT depend on whether it occurs acute or chronic. The affected systems are the neuromuscular, ectodermal, ocular, cardia and neuropsychiatric system and manif
Sponsor: University of Aarhus

Current Primary Outcome: Frequency of hypoparathyroidism, pseudohypoparathyroidism and autosomal dominant hypocalcaemia and its consequences [ Time Frame: One year ]

Original Primary Outcome: Frequency of hypoparathyroidism, pseudohypoparathyroidisme and autosomal dominant hypocalcaemia and its consequences [ Time Frame: One year ]

Current Secondary Outcome:

Original Secondary Outcome:

• Muscle function [ Time Frame: One year ]
  Muscle strength determined by using a dynamometer
• Postural balance [ Time Frame: One year ]
  Assessed using a stadiometer
• Quality of Life [ Time Frame: One year ]
  Assessed by SF-36v2 and WHO-Five Well-Being Index
• Calcium homeostasis, bone metabolism, and body composition [ Time Frame: One year ]
  Measurements of calcitropic hormones, biochemical markers of bone turnover. BMD and body composition is measured by DXA and pQCT
• Tonometry [ Time Frame: One year ]
• Questionary [ Time Frame: One year ]
  Present and previously diseases, fracture anamnesis, incident of disturbances in the calcium metabolism, fractures and disease in first-degree relatives, physical activity, consumption of dietary products, coffee, tea, tobacco and alcohol. Diet- and sunbathing habits. Medical anamnesis, including use of calcium and/or vitamin D supplement, vitamin supplement, dietary supplement and the use of natural products.

Dates:
Date Received: December 20, 2011
Date Started: August 2011
Date Completion:
Last Updated: June 30, 2014
Last Verified: January 2013