(CNN) Sia revealed something deeply personal on Twitter Friday.

"I just wanted to say to those of you suffering from pain, whether physical or emotional, I love you, keep going," Sia tweeted. "Pain is demoralizing, and you're not alone."

Ehlers-Danlos syndrome is a group of disorders that affects connective tissues that support the skin, bones, blood vessels and other organs and tissues, according to the National Institute of Health's Library of Medicine. Many people with the condition have soft, fragile skin and bruise and scar easily.

There are 13 types of Ehlers-Danlos syndrome, as of 2017, according to NIH. People with the "classical" form of the condition may experience wounds that leave scars that widen over time, the NIH states.

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