The Ehlers-Danlos syndromes are a collection of thirteen multi-systemic, heritable disorders affecting connective tissue, the most abundant tissues in the body. With the exception of the hypermobile Ehlers-Danlos syndrome, each type is a distinct entity defined by mutations in a single or small set of genes. Common features among the types include joint hypermobility, skin fragility, chronic pain, and fatigue. More severe types, such as Vascular Ehlers-Danlos syndrome, can be life-threatening, as fragile blood vessels and internal organs can spontaneously rupture.