The goal of this observational study is to create a single macro registry system with data collection on common clinical features, grouping the different rare diseases (RD).

Moreover, the specific goals are to generate an alert system for possible cases of RD with data from the electronic medical record, to describe the occurrence of RD in the evaluated population, to characterize the population, to describe patterns of diagnosis and treatment of RD present at the time, and to explore patient-reported outcomes.

Rare Diseases (RD) pose a health challenge due to their complexity and low prevalence, generating a burden in terms of morbidity and mortality and costs.

The fragmentation of data on these diseases makes it difficult to understand them comprehensively. Therefore, the creation of a macro institutional registry that brings together information on RD would facilitate research in this field.

The registries are organized systems of systematic data collection of a large number of patients quickly and efficiently on a particular disease at a given time.

The main difficulty of the registries is the guarantee of the quality of their data.

The main objectives of the registry are:

Understand risk factors and prognosis. Evaluate the diagnostic and therapeutic comparison with current standards. Advance knowledge of the disease to optimize the assessment, treatment and monitoring of patients.

Analyze the effectiveness of new therapies. Studying differences between populations. Quickly estimate the morbidity, mortality and resource utilization associated with a disease entity.

Examine the course of a disease Formulate novel hypotheses for further prospective studies.

Inclusion Criteria:

• Clinical and/or molecular diagnosis of any of the following rare diseases: Amyloidosis, Sarcoidosis, Phacomatosis, Pheochromocytoma, Paraganglioma, Von Hippel-Lindau Disease, Immunoglobulin G4-Related Disease, Demyelinating Diseases, Inborn Errors of Metabolism, Eosinophilic Gastrointestinal Disorders, Hypertrophic Cardiomyopathy, Gaucher Disease, Congenital Adrenal Hyperplasia, Hereditary Angioedema, Pulmonary Hypertension, Wilson Disease, Vascular Anomalies, Mastocytosis, Multiple Endocrine Neoplasia, Inflammatory Bowel Diseases, Prader-Willi Syndrome, Hirschsprung Disease, or Cushing Syndrome.
• Must be followed at Hospital Italiano de Buenos Aires.

Exclusion Criteria:

- Refusal to participate in the study or in the informed consent process.

People of any age, with a confirmed diagnosis of one or more rare diseases and followed up at Hospital Italiano de Buenos Aires, categorized as such according to the Orpha code from the List of Rare Diseases of the Ministry of Health of the Nation.

There is a plan to make individual participant data (IPD) available to other researchers by contacting the IP (María Lourdes Posadas Martínez, Soledad Kleppe, Marcelo Martín Serra) with a letter of intent on the protocol to be carried out. If you agree, the protocol will be presented to the ethics committee and work will be carried out in accordance with current regulations.