Observational, registry, prospective, non-interventional collection of CUA patient data. Patient treatment is carried out within clinical routine, at the discretion of the physicians and according to existing treatment guidelines. Participating physicians will not be subject to any instructions with regard to the diagnosis and therapy of their patients.

Calcific uremic arteriolopathy (CUA, calciphylaxis) is a rare disease (ORPHA280062) with dramatically high mortality characterized clinically by the occurrence of painful debilitating cutaneous lesions and ulcerations. Median survival time is about 1.5 years. Many uncertainties still exist about risk factors and optimal therapy. CUA mainly occurs in patients with severe renal insufficiency or ESRD.

The aim of the present initiative is to establish an international (European) observational registry for CUA patients. This registry will help to reach a critical mass of CUA patients, will allow novel insights into pathophysiology, and will help establishing systematically an overview upon risk factors and long-term outcome of CUA patients. The design of the international registry is supposed to adopt the structure of the presently running nation-wide German calciphylaxis registry.

The investigators plan to initiate a registry in which treating physicians can provide data upon demographics, clinical picture, comorbidities, medical treatments and laboratory data at the time of diagnosis and serial follow-up time points. In addition investigators will build-up a biobank for full blood, serum and plasma samples as well as tissue samples.

The registry will allow investigations regarding potential subgroups of patients (proximal versus distal forms of CUA), geno-phenotype correlations, description of international state-of-the-art treatment, and identification of preventive tools, risk factors and biomarkers for estimation of prognosis.

Furthermore, the registry will be the nidus for further scientific exchange between experts and clinicians on the field of uremic vascular calcification.

Inclusion Criteria:

• diagnosed CUA according to the judgement of locally treating physicians, who have the option to ask for external diagnostic advice from the country-specific sub-investigators
• Male or female aged > 18 years
• Written informed consent prior to study participation
• The subject is not mentally or legally incapacitated

Exclusion Criteria:

• The subject is not able to give informed consent

Patients with diagnosed CUA