Familial Primary Hypomagnesemia With Hypocalcuria

The goal of this National Registry is to is to collect information from patients with rare kidney diseases, so that it that can be used for research. The purpose of this research is to: * Develop Clinical Guidelines for specific rare kidney diseases. These are written recommendations on how to diagnose and treat a medical condition. * Audit treatments and outcomes. An audit makes checks to see if what should be done is being done and asks if it could be done better. * Further the development of future treatments. Participants will be invited to participate on clinical trials and other studies. The registry has the capacity to feedback relevant information to patients and in conjunction with Patient Knows Best (Home - Patients Know Best), allows patients to provide information themselves, including their own reported quality of life and outcome measures.