The general objective of this research is to evaluate the characteristics of bone mineralisation in patients with Marfan syndrome or Ehlers-Danlos syndrome on a large case series.

In particular we intend to obtain data regarding the characteristics of bone mineralisation, as well as their variation over time and the relationships existing with other clinical-anamnestic parameters, in patients with Marfan syndrome or Ehlers-Danlos syndrome by retrospectively analysing (data already collected for normal clinical practice and already available at the hospital) the case history of the Cardiovascular genetic center at IRCCS Policlinico San Donato and the related Computerized Bone Mineralometry (MOC) examinations performed at the Radiology Service of the same hospital between 1 September 2019 and 31 December 2022.

Inclusion Criteria:

• Subjects with Marfan syndrome and Ehlers-Danlos syndrome according to the revised reference criteria belonging to the Cardiovascular genetic center at IRCCS Policlinico San Donato and the Reference Centre for Ehlers-Danlos Syndromes Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico;
• Adult and paediatric subjects who have performed at least one Bone Mineral Densitometry within the observation period of the study.

Exclusion Criteria:

• Presence of prostheses in the spinal column;
• Presence of prostheses in the coxofemoral joint;
• Oncological bone diseases reported in history.

Marfan syndrome is a rare connective tissue disease with autosomal dominant transmission, characterised by altered production of the glycoprotein fibrillin-1 (FBN1), resulting from mutations in the gene encoding it.The complications most associated with the risk of mortality and morbidity are those affecting the cardiovascular system and those affecting the musculoskeletal system (spinal changes and chest deformities).

Ehlers-Danlos syndrome has an estimated prevalence of 1:5000 individuals and presents a pathological phenotype affecting the connective tissues that support the integumentary, skeletal, cardiovascular, and other organs and tissues. As in Marfan syndrome, marked alterations in the skeletal system (spine, thorax) and, in the vascular forms, a high risk of aneurysms and aortic and/or small and medium artery dissection, are found in those with Ehlers-Danlos syndrome.