Establishing the diagnosis of Ehlers Danlos Syndromes (EDS)/generalized hypermobility spectrum disorders (G-HSD) is often problematic for patients. The absence of a precise unifying diagnosis in patients results in a significant emotional burden on the patient and caregivers, not to mention the hidden costs, including multiple recurring visits to several medical specialists and associated social and economic costs. To date, while collagen ultra-scale morphological heterogeneity has been used to comment on an EDS diagnosis, the mechanical properties of the collagen remain mostly unexplored.

From a biophysical point of view, collagen affected with hEDS can be described as biomechanically deficient. In the case of EDS, the skin's abnormal elasticity can be directly related to the organization of the collagen network within the dermis. Quantitative Nanohistology (QNH) is a newer method to evaluate both the structural and mechanical properties of collagen in-situ histological sections.

Therefore, the aim of this study is to define histo-biophysical markers of two most common types of EDS i.e. classical EDS (cEDS) & hypermobile EDS (hEDS) at the single collagen fibrils level and matrix and to further explore the origin of collagen fibril properties deficiency in hEDS and cEDS.

Inclusion Criteria:

• Adults aged between 18 and 60 years who can provide informed consent in English
• Able to read, speak, and comprehend English without the assistance of a translator
• Have been diagnosed with hypermobile EDS as per the 2017 EDS criteria; or with genetically confirmed classical EDS (age and sex-matched). This diagnosis is carried out by the UHN GoodHope EDS clinic routinely for all patients on the basis of clinical exam and genetic testing, if indicated.

Exclusion Criteria:

• Subjects under the age of 18
• Unable to speak, read and comprehend English
• Unable to provide consent (cognitive impairment)
• Pregnant women

Individuals with classical EDS and hypermobile EDS