Studies of States With Resistance to Vitamin D and Parathyroid Hormone

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Studies of States With Resistance to Vitamin D and Parathyroid Hormone

Conditions
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Rickets, Pseudopseudohpoparathyroidism, Hypocalcemia, Pseudohypoparathyroidism, Osteomalacia

Participation Criteria
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Eligibility Criteria
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INCLUSION CRITERIA: Patients, from 2 months to 100 years of age, of either sex M or F, with vitamin D resistance, rickets, osteomalacia, pseudohypoparathyroidism, pseudo-pseudohypoparathyroidism, or suspicion of these or related disorders based upon the appropriateness of their problem to ongoing investigations. Current investigations are focused principally upon the inclusion of subjects with, or suspected of having, hypocalcemia likely due to a resistance to parathyroid hormone, including subjects who have a diagnosis, or likely diagnosis, of pseudohypoparathyroidism or pseudopseudohypoparathyroidism.

Ages Eligible for Study
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Minimum Age: 2 Months
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Study Cohort<br>Patients of any age or sex with vitamin D resistance, rickets, osteomalacia, pseudohypoparathyroidism, pseudo- pseudohypoparathyroidism, or suspicion of these or related disorders | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| This study will provide information about problems relating to calcium in the blood, urine, and bones | This is a natural history protocol, directed at diagnosing and managing the general clinical features in these patients. In addition the full clinical expression of certain rare disorders (target resistance to 1,25(OH)2D, pseudohypoparathyroidism, and pseudo- pseudohypoparathyroidism) will be characterized further. Some of these patients or their relatives will be entered into additional protocols, where appropriate for example, protocols to characterize the molecular causes of these disorders. | take one to two weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Rickets, Hypocalcemia, Albright Hereditary Osteodystrophy, Pseudohypoaldosteronism, Natural History