PPI Supplementation to Fight ECtopIc Calcification in PXE

Inclusion Criteria: * Patients (\>18 years and \<65 years), men and women, presenting a clinically and biologically authenticated PXE (genotype + phenotype) according to the international diagnostic criteria (26). * Efficient contraceptive method in woman of childbearing age at inclusion and during the overall study * Patient affiliated to a social security insurance * Signed informed consent * Patient without acute complication linked or not to the pathology at the time of the study NON-INCLUSION CRITERIA * Renal insufficiency (i.e. defined by a renal clearance \<30ml / min / 1.73 m²) * Patients with osteomalacia * Patients with chronic diarrhea (\> 1 month) * Pregnancy, lactating or fertile women who may wish to become pregnant within three years. * Any other medical condition that may be considered in the opinion of the Principal Investigator. * Use of bisphosphonate during last 5 years. * Hypocalcemia (calcium \<2.20 mmol/L and ionized calcium \<1.15 mmol/L) \*. * Vitamin D deficiency \<35 nmol/L \* * Enrollment in another inteventional clinical trial which could interfere with the present study * patients (\>18 years) protected by law * After correcting the hypocalcemia and/or vitamin D deficiency, a participant is again suitable for participation in the trial, as long as the participant meets the inclusion criteria.