What is Ehlers-Danlos syndrome that singer Sia is suffering from?

Ehlers-Danlos syndrome is a group of disorders affecting connective tissues supporting the skin, bones, blood vessels and other organs and tissues. They're generally characterised by joint hypermobility (joints stretch further than normal) and skin hyperextensibility (skin stretches further than normal). There are 13 types of Ehlers-Danlos syndrome and many with the disorder bruise or scar easily.