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.

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

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.

Two years after the last publication

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