Renal and Vascular Phenotypic Characterization of Patients With Enamel Renal Syndrome Due to a Pathogenic Variant of the FAM20A Gene and Pathophysiological Study of Ectopic Calcifications (FAM-Cal)

In the research, the investigators will characterize the renal and vascular damage and look for factors favoring the formation of calcification induced by enamel renal syndrome.

Patients will undergo four investigations, as part of their routine care, to assess their renal impairment. Each investigation will require a day in the Physiology Department of the George Pompidou European Hospital.

The 4 tests are designed to

• precisely measure your renal filtration capacity,
• evaluate your body's calcium and phosphate regulation,
• evaluate your capacity to regulate the elimination of water from the body
• assess your body's ability to regulate "acid" intake. As part of the research, an additional 20 ml blood sample and a urine sample will be taken during the other samples taken as part of routine care.

Healthy volunteers will undergo blood and urine tests, dental X-rays and renal ultrasound. For healthy volunteers, the aim of the dental X-ray and renal ultrasound is to check that there are no dental or renal abnormalities, so as to rule out not only email-rein syndrome, but also any dental or renal abnormalities that might resemble it. The aim of blood and urine sampling is to measure various molecules that promote calcification or inhibit the calcification process, so as to be able to compare results obtained in healthy subjects with those obtained in patients with enamel renal syndrome. Each healthy subject will be selected to be matched by age and sex to each of the patients included in the study.

Study Overview

• Status: Not yet recruiting
• Conditions: Enamel Renal Syndrome
• Intervention / Treatment: Diagnostic test: urinary proteome; Diagnostic test: urinary metabolome; Diagnostic test: Evaluation of plasma mineralization factors; Diagnostic test: Renal ultrasound; Radiation: dental panoramic x-ray; Biological: Blood and urine minimal biology

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Cléo BOURGEOIS; Phone Number: +33 0156095638; Email: cleo.bourgeois@aphp.fr
• Study Contact Backup: Name: Elise Bouderlique, MD; Phone Number: +33 0156092866; Email: elise.bouderlique@aphp.fr

Study Locations

• France
  • Paris, France, 75015
    • HEGP - clinical investigation center
    • Contact: Marine Livrozet; Phone Number: 0156095854; Email: marine.livrozet@aphp.fr
    • Principal Investigator: Marine Livrozet
  • Paris, France, 75015
    • HEGP - physiology department
    • Contact: Elise Bouderlique; Phone Number: +33 0156092866; Email: elise.bouderlique@aphp.fr
    • Principal Investigator: Elise Bouderlique

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Informed patient who does not object to participating in the study
• Age ≥ 18 years
• Be affiliated to a social security scheme or be a beneficiary of such a scheme
• Able to understand the interest and constraints of the study
• Suffering from enamel-renal syndrome with a proven pathogenic variant of FAM20A

Exclusion Criteria:

• Pregnancy
• Breast-feeding
• Simultaneous participation in a therapeutic trial
• Patient under guardianship or curatorship
• Patient under court protection or family guardianship
• Patient under AME
• Enamel-renal syndrome with pathogenic variation in a gene other than FAM20A

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Healthy volunteers; The control group will be made up of healthy volunteers, in order to provide a reference population, matched for the analyses carried out as part of the research, i.e. metabolome, proteome and plasma factors of mineralization.	Diagnostic test: urinary proteome; Volume 2 ml, with protease inhibitor made one time for each arm of the protocol; Diagnostic test: urinary metabolome; Sample collected once in the protocol for each arm.; Diagnostic test: Evaluation of plasma mineralization factors; Complementary plasma analysis during another blood sample collection for both arms; Other Names: Osteoprotegerin; Propensity score; dp-uc MGP; Fetuin A; Diagnostic test: Renal ultrasound; Verification of normal renal morphology, absence of nephrocalcinosis; Radiation: dental panoramic x-ray; Verification of normal dentition; Biological: Blood and urine minimal biology; Fasting blood: creatinine, blood ions (Na + K + Cl + CO2 + Proteins), calcium, phosphate, CBC (Complete Blood Count), liver function tests, lipid profile); Morning fasting urine: creatinine, calcium, phosphate, protein, urinalysis (ECBU)
Experimental: Enamel Renal Syndrome Patient; The population to be studied is a population of adult patients suffering from enamel renal syndrome with FAM20A mutation.	Diagnostic test: urinary proteome; Volume 2 ml, with protease inhibitor made one time for each arm of the protocol; Diagnostic test: urinary metabolome; Sample collected once in the protocol for each arm.; Diagnostic test: Evaluation of plasma mineralization factors; Complementary plasma analysis during another blood sample collection for both arms; Other Names: Osteoprotegerin; Propensity score; dp-uc MGP; Fetuin A

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glomerular filtration rate	Glomerular filtration rate measurement by measure of renal 99mTc-DTPA clearance	Up to 18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of urine proteome between patients and healthy volunteers	Identification of candidate mechanisms to approach the pathophysiology of ectopic calcifications through the study of the urinary proteome	Up to 18 months
Maximal urine osmolality	Evaluation of water regulation by water deprivation test, urine collection after deprivation.	Up to 18 months
Level of dp-uc MGP	Identification of candidate mechanisms for approaching the pathophysiology of ectopic calcifications by assaying plasma inhibitors of biomineralization.	Up to 18 months
Level of Fetuin A	Identification of candidate mechanisms for approaching the pathophysiology of ectopic calcifications by assaying plasma inhibitors of biomineralization.	Up to 18 months
Level of Osteoprotegerin	Identification of candidate mechanisms for approaching the pathophysiology of ectopic calcifications by assaying plasma inhibitors of biomineralization.	Up to 18 months
Propensity score	Identification of candidate mechanisms for approaching the pathophysiology of ectopic calcifications by assaying plasma inhibitors of biomineralization.	Up to 18 months
Ammonium chloride urine flow	Urine collection to evaluate the acid regulation after oral ammonium chloride load test.	Up to 18 months
calciuria rate	Urine collection in order to evaluate calcium regulation.	Up to 18 months
Ratio TmPi/DFG	Blood and urine collection in order to evaluate phosphate regulation	Up to 18 months
Calcium score	Thoracic, abdominal and pelvic scan perform in order to evaluate vascular calcium content.	Up to 18 months

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Collaborators: Université de Liège; Institut Necker Enfants Malades; Fondation Université de Paris

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): October 30, 2029
• Study Completion (Estimated): October 30, 2029

Study Registration Dates

• First Submitted: May 28, 2025
• First Submitted That Met QC Criteria: December 12, 2025
• First Posted (Actual): December 16, 2025

Study Record Updates

• Last Update Posted (Actual): December 16, 2025
• Last Update Submitted That Met QC Criteria: December 12, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: FAM20A; enamel renal syndrome
• Additional Relevant MeSH Terms: Amelogenesis imperfecta nephrocalcinosis; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Diagnostic Imaging; Radiography; Dentistry; Radiography, Dental; Diagnosis, Oral; Blood Specimen Collection; Radiography, Panoramic
• Other Study ID Numbers: APHP240692; 2024-A02589-38 (Other Identifier: Agence nationale de sécurité du médicament et des produits de santé); 24.05810.000413 (Other Identifier: Commission Nationale des Recherche Impliquant la Personne Humaine)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The deidentified individual participant data (IPD) that support the results reported in publications may be shared. Additionally, the IPD outlined in the protocol for a planned meta-analysis may also be made available. A data dictionary defining each field will be made available concurrently with the data transmission.
• IPD Sharing Time Frame: Two years after the last publication

IPD Sharing Access Criteria

Data sharing requires approval from both the sponsor and the Principal Investigator (PI), contingent upon a scientific project and the PI team's scientific contribution. The founder may also participate in the decision-making process.

Teams seeking to acquire IPD must engage with the sponsor and the IP team to discuss the scientific (and commercial) objectives, the specific IPD required, the preferred data transmission format, and the proposed timeline. The necessity to inform patients about data sharing or the obligation to undertake procedures with data protection authorities will be evaluated.

The provision of data through the secure institutional tools of the sponsor AP-HP will be prioritized.

Technical feasibility and financial support considerations will precede the obligatory formalization of a contract, including detailed description of data processing and general and specific security measures.

The processing must adhere to the European General Data Protection Regulation

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No