View clinical trials related to Pseudohypoparathyroidism.
Filter by:PTH secretion defects (grouped under the name hypoparathyroidism) are due to abnormalities in the PTH gene, abnormalities in the development of the parathyroid glands which synthesize PTH or abnormalities of the calcium sening receptor whose role is to adapt PTH level to ambient calcium level. In contrast, primary hyperparathyroidism in children is also exceptional; expressed by hypercalcemia, with a renal and bon risk. Pseudo-hypoparathyroidism, now known under the term inactivating PTH / PTHrP Signaling Disorder or iPPSD, are rare pathologies characterized by resistance to the action of PTH sometimes associated with other symptoms, in particular chondrodysplasia. They are linked to a defect in the action of a factor in the signaling pathway of G protein-coupled receptors that activate the production of cyclic AMP (cAMP). IPPSDs are most often due to a molecular defect in the GNAS gene, subject to parental imprint. Fibrous dysplasia / McCune-Albright syndrome is a rare disease caused by somatic "gain-of-function" mutations in the GNAS gene located on chromosome 20q13 leading to activation of the protein Gαs and inappropriate production of intracellular cyclic adenosine monophosphate (cAMP). The clinical phenotype is determined by the location and extent of the tissues affected by this mutation. Autotaxin (ATX) is a protein secreted by different tissues including the liver, fatty tissue, and bone. Today, ATX is described as the major source of LPA in the bloodstream. LPA interacts with one of its receptors on the surface of the cell membrane. Depending on the receptor engaged, one or more Gα subunits (G12 / 13, GQ, Gi / o or Gs) will activate multiple cell signaling pathways. In bone, ATX is expressed by osteoclasts and osteoblasts. Recent laboratory data have shown that PTH stimulates ATX expression in osteoblasts in a dose-dependent manner. The objective of this study is to provide clinical proof of concept that the PTH / Gαs / ATX pathway is truly significant in physiology and pathology, by studying the full spectrum of PTH and GNAS pathologies. If this proof of concept is obtained, therapeutic applications will probably be possible in the long term.
Hypoparathyroidism (HypoPT) is a disease with inadequate production of parathyroid hormone (PTH) from the parathyroid glands leading to hypocalcemia. The most common form is postsurgical HypoPT due to neck surgery resulting in removed or damaged parathyroid glands. HypoPT is a complex disease with a reduced Quality of life, mild cognitive impairment and in some patients have brain calcifications. The aim of the present study is to investigate the cognitive function in patients with postsurgical and non-surgical (HypoPT) by neuropsychological assessments and magnetic resonance imaging (MRI). The investigators will apply a contrast-enhanced MRI based method to HypoPT patients and age- and gender matched controls to examine whether capillary dysfunction can be detected, and whether symptom severity across patients correlates with the degree of capillary dysfunction in certain brain regions. To our knowledge there have been no previous studies on cognitive impairment and its origin in patients with HypoPT. The investigators hypothesize that the symptoms of HypoPT patients represent various degrees of capillary dysfunction, which interfere with their brain function.
This study will test an investigational drug, theophylline, in children with pseudohypoparathyroidism type 1a (PHP1a). This study involves a 3 day visit to the Vanderbilt Clinical Research Center.
Pseudohypoparathyroidism type 1a (PHP1a) is a rare disease that causes childhood obesity and learning difficulties. This study will investigate eating behaviors and perform cognitive testing on children with PHP1a. The investigators will compare their results to those of healthy siblings and other obese children.
OBJECTIVES: Determine the relationship between serum calcium concentrations and parathyroid hormone secretion in patients with pseudohypoparathyroidism.
Patients with confirmed or suspected states with resistance to vitamin D or parathyroid hormone (PTH) will be admitted for diagnosis, treatment review with suggestions for modifications to the current or new treatment and for inclusion in other protocols. These states include hypocalcemia, rickets, osteomalacia, pseudohypoparathyroidism. Resistance to a factor is manifested by deficient bioeffect despite high levels of the factor in blood. Patients will be tested with multiple indices of mineral metabolism to establish the diagnosis and examine the spectrum of the underlying disorder. The principal therapies will be combinations of calcium, phosphate, and a vitamin D analog. Selected patients will have localization and surgery to remove a tumor that causes renal wasting of phosphate. Patients will also be considered for entry into other research protocols.