Fibromuscular dysplasia (FMD) is localized structural defects in the arterial wall, whose innate or acquired character is still unknown. This segmental non atheromatous injury, leads to stenosis of the arteries of small and medium caliber. Renal arteries are the most commonly affected with 60-75% of total fibrodysplasia. Three histological subtypes have been described: intimal, medial and peri-medial. They are not mutually exclusive and can be observed in the same patient.

This is a rare blood disease, occurring in children and young adults. In this young population with long life expectancy, these aneurysmal lesion are associated with 10% risk of rupture. To date, no data have shown in the literature that FMD is link to genetic causes, or if there is specific histopathologic lesions for non-atherosclerotic renal artery aneurysms.

To answer these questions, Cardiovascular Surgery Unit of the University Hospital of Saint-Etienne, French national reference center for renal artery surgery, in association with the Reference Center for Rare Vascular Disease in Paris, designed the first study for pathological and genetic characteristics of dysplastic renal artery aneurysms in young patients.

Inclusion Criteria:

• Patients with one or more Renal artery aneurysm (RAA), not eligible for endovascular treatment, have been operated at the Hospital of Saint-Etienne, with tissue (adjacent part and aneurysm) cryopreserved in liquid nitrogen in renal lab and then sent in genetic lab in Georges Pompidou European Hospital (EHGP ).
• Patient (or parent/person having parental authority) Affiliate or entitled to a social security scheme.
• Signature of patient consent (or parents or holder of parental authority)

Exclusion Criteria:

• Patient not included in the tissue collection in Georges Pompidou European Hospital (EHGP ).
• Patient refusing to participate in the study and / or genetic analysis or, for juvenile patients, parents or holder of parental authority refusing the minor patient to be involved in the study and / or genetic analysis.
• Patient with FMD whose samples in the tissue collection did not concern aneurysm.

Patients with one or more Renal artery aneurysm (RAA), not eligible for endovascular treatment, have been operated at the Hospital of Saint-Etienne, with tissue (adjacent part and aneurysm) cryopreserved in liquid nitrogen in renal lab and then sent in genetic lab in EHGP.