Primary outcome is to compare the frequency and clinical features of spinal symptoms between Marfan patients with dural ectasia (cases) and those without (controls).

1. / Frequency of orthostatic headaches
2. / Frequency of low back pain due to orthostasis
3. / Frequency of low back pain during Vasalva maneuvers
4. / Frequency of lumbar claudication
5. / Frequency of root claudication

Secondary outcomes are to compare activity limitations, quality of life and intensity of low back and radicular pain between Marfan patients with dural sac ectasia (cases) and those without (controls).

1. / Average intensity of back pain measured on a self-administered digital scale (0 = no pain and 100 = maximum pain)
2. / Average intensity of radicular pain measured on a self-administered digital scale (0 = no pain and 100 = maximum pain)
3. / Activity limitations specific to the lumbar spine measured using the self-administered Oswestry Disability Index questionnaire (ODI, 0 = no limitations and 100 = maximum limitations)
4. / Physical component of quality of life measured using the physical component of the self-administered questionnaire 12-Item Short Form Health Survey (SF-12, 9.95 = worst quality of life imaginable, 70.02 = worst quality of life imaginable )
5. / Mental component of the quality of life measured using the mental component of the SF-12 self-administered questionnaire (5.89 = worst quality of life imaginable, 71.97 = worst quality of life imaginable)

Marfan's disease is a rare condition. Clinical phenotypes are heterogeneous. Among the abnormalities of the spine, dural ectasia is common with a prevalence of 66%. This is a major sign of Ghent's diagnostic criteria. To our knowledge, the clinical and functional signs associated with dural sac ectasia have never been described with precision. Only a few uncontrolled case series have been published. This is the case of the study by Foran and colleagues published in the American Journal of Genetics in 2005 which included 22 patients with Marfan disease with dural ectasia questioned about their symptoms and quality of life. We hypothesize the existence of a clinical and functional spinal phenotype specific to dural ectasia in patients with Marfan disease.

Inclusion Criteria:

• Marfan disease according to the Ghent criteria revised in 2010
• Patients followed at the CNMR in Bichat
• Adults ≥18 years old and ≤ 55 years old (to limit the incidence of degenerative lumbar pathologies)
• Patient not opposing the research
• Mastery of the French language

Exclusion Criteria:

• History of lumbar surgery <1 year
• Specific pathologies of the spine (tumor, infection, trauma, fracture, inflammatory rheumatism)
• Inability to write, read or speak French
• Cognitive or behavioral problems making assessment impossible
• Patients receiving AME
• Patients under tutorship or curatorship

Patients screened and selected at the CNMR at Bichat Hospital will receive a letter containing the information note and a self-questionnaire to complete.

Patients can reach Dr Troussier by phone or email to ask any questions. Patients will return a copy of the completed briefing note and self-questionnaire by post.

In the event of the presence of dural sac ectasia, patients will also be asked to send in the reply letter a copy of an imaging report, MRI or lumbar CT or TAP, or failing that an account- medical report mentioning this presence.