Parathyroid Hormone (PTH) Homeostasis in Bartter Syndrome

NCT01021280 | Unknown

• 1 other identifier: Sor492809ctil
• Study Type: observational
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

Parathyroid hormone (PTH) gland calcium sensing receptor (CASR) regulates PTH secretion. CASR is also expressed in nephron thick ascending limb (TAL). Bartter syndrome (BS), a normotensive hypokalemic tubulopathy, may be due to mutations in different TAL channels, including the potassium channel ROMK. Mutations in CASR may also cause BS through its effects on ROMK function. However, it is unknown whether ROMK mutations exert any effects on CASR function and PTH physiology. Preliminary data from our center shows that PTH levels were specifically elevated in type II (where ROMK is mutated) and not in type IV (where another gene, Barttin is defective) BS, without a common explanation. We assume that the mutation in ROMK may cause a dysregulation of PTH secretion via possible interaction with CASR. The purpose of this study is: to investigate the PT-gland function and regulation in BS. Methods: Patients with BS type II and IV and normal controls will undergo a standard protocol of controlled ionic hypo- and hypercalcemia, during which PTH secretion, phosphate balance and calcium excretion will be followed. Calcium Vs PTH response curves will be generated and compared. Expected impact and benefit: the results of this study will help understand the mechanisms of PTH regulation beyond CASR.

Conditions

Hypocalcemia; Hypercalcemia

Keywords

Bartter syndrome,; parathyroid hormone,; calcium sensing receptor,; ROMK channel; Barttin gene; PTH response to hypo- and hypercalcemia

Study Arms (3)

Type II BS

Adolescents and young adults with type II Bartter syndrome

Type IV BS

Adolescents and adults with type IV Bartter syndrome

Controls

Age and sex- matched controls

Eligibility Criteria

• Age: 14 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Adolescent and young adult patients with Bartter syndrome and age- and sex- matched controls.

You may qualify if:

• Bartter syndrome
• Normal Vitamin D status

You may not qualify if:

• Age \< 14 yrs

Sponsors & Collaborators

• Soroka University Medical Center: lead
• Ben-Gurion University of the Negev: collaborator

Study Sites (1)

Soroka University medical Center

Beersheba, 84101, Israel

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Serum and urine will be later analyzed for FGF-23 and other key molecules in PTH homeostasis.

MeSH Terms

Conditions

Hypocalcemia; Hypercalcemia; Bartter Syndrome

Condition Hierarchy (Ancestors)

Calcium Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Water-Electrolyte Imbalance; Renal Tubular Transport, Inborn Errors; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Hyperaldosteronism; Adrenocortical Hyperfunction; Adrenal Gland Diseases; Endocrine System Diseases

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head, Pediatrics Department A and Pediatric Nephrology Service

Study Record Dates

• First Submitted: November 25, 2009
• First Posted: November 26, 2009
• Study Start: January 1, 2013
• Primary Completion: December 1, 2013
• Study Completion: June 1, 2014
• Last Updated: June 14, 2012

Record last verified: 2012-06

Locations

IL (1)