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Studying Phosphorus Metabolism

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00066183
Recruitment Status : Completed
First Posted : August 5, 2003
Last Update Posted : March 4, 2008
Information provided by:
National Institutes of Health Clinical Center (CC)

Tracking Information
First Submitted Date August 4, 2003
First Posted Date August 5, 2003
Last Update Posted Date March 4, 2008
Study Start Date August 2003
Primary Completion Date Not Provided
Current Primary Outcome Measures Not Provided
Original Primary Outcome Measures Not Provided
Change History
Current Secondary Outcome Measures Not Provided
Original Secondary Outcome Measures Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title Studying Phosphorus Metabolism
Official Title Studies in Phosphorus Metabolism
Brief Summary

Phosphorus and phosphate irons play critical roles in bone structure and essential cellular functions.

The purpose of this study is to learn more about the factors and hormones that regulate phosphorus in the body by collecting blood and urine samples from patients with disorders of phosphate control.

Both children and adults will be enrolled in this study. Researchers will collect blood and urine samples from participants on multiple occasions (2 to 6 times). Some blood specimens will be taken after an overnight fast and participants may be asked to collect all their urine during a 24-hour period. Researchers will analyze these blood and urine samples to better understanding how the body handles phosphorus.

Detailed Description

Phosphorus and phosphate ions play an important role in cellular metabolism as well as bone structure. Scientific evidence suggests that, in addition to Vitamin D and PTH systems, novel factors, such as Fibroblast Growth Factor 23 (FGF-23) and Matrix extracellular phosphoglycoprotein (MEPE), may play an important role in phosphorus regulation. These factors have been best studied in rare genetic and acquired phosphate wasting disorders such as tumor induced osteomalacia (TIO), X linked hypophosphatemia (XLH) and autosomal dominant hypophosphatemic rickets (ADHR). Patients with other abnormal phosphate regulating states such as hyperparathyroidism and hypoparathyroidism, pseudohypoparathyroidism etc. undergoing phosphorus-altering interventions may provide important insight into the role of these hormones.

We are proposing an observational study with collection of blood and urine samples to study both established (e.g. mineral ions, bone markers, PTH-Vit D system, TMP-GFR) and novel (e.g. FGF-23 and MEPE) constituents of the phosphorus metabolism pathway. Patients with abnormal phosphorus regulating states will be enrolled and we will study the natural history of their disease and the effects of specific interventions that are likely to change phosphorus balance.

The outcome will potentially aid understanding of this new field of mineral regulating hormones and generate both interest and research in phosphorus metabolism. It is hoped that this will also encourage clinical trials in treatment of phosphate wasting disorders.

Study Type Observational
Study Design Not Provided
Target Follow-Up Duration Not Provided
Biospecimen Not Provided
Sampling Method Not Provided
Study Population Not Provided
Condition Phosphorus Metabolism
Intervention Not Provided
Study Groups/Cohorts Not Provided
Publications *

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status Completed
 (submitted: June¬†23,¬†2005)
Original Enrollment Same as current
Study Completion Date January 2005
Primary Completion Date Not Provided
Eligibility Criteria


Patients of any age, gender or ethnicity who will help fulfill the objectives laid out in Section II.

We propose to study patients primarily enrolled in other clinical center protocol(s). They will continue to receive treatment/ interventions per the original protocols.


Patients with significant cognitive impairment who are unable to give informed consent or patients having other significant mineral disturbances that could confound the parameters being studied will be excluded.

Sexes Eligible for Study: All
Ages Child, Adult, Older Adult
Accepts Healthy Volunteers No
Contacts Contact information is only displayed when the study is recruiting subjects
Listed Location Countries United States
Removed Location Countries  
Administrative Information
NCT Number NCT00066183
Other Study ID Numbers 030254
Has Data Monitoring Committee Not Provided
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement Not Provided
Responsible Party Not Provided
Study Sponsor National Institute of Dental and Craniofacial Research (NIDCR)
Collaborators Not Provided
Investigators Not Provided
PRS Account National Institutes of Health Clinical Center (CC)
Verification Date January 2005