Sjogren's (pronounced SHOW-grenz) is an auto-immune disease. In it, the body is attacking the glands that secrete mucus.
It afects up to four million Americans of all ages.
A teenager in Montgomery County we spoke with applauds Venus going public.
15-year-old Sarah Gleason's bookshelf is lined with trophies from when she was younger. She played softball, soccer, did dance, baton and her favorite cheerleading.
Sarah says, "I'm very into school spirit so it's great to be able to cheer on your school."
But Sarah got sick when she was 7, and eventually had to give up her activities, because of severe fatigue.
"We would go shopping and all of a sudden, she would sit all of a sudden in the middle of an aisle," says her mother, Ruth.
Sarah also has dry eyes and dry mouth, plus joint pain.
"Sometimes I feel like my joints are like triple in size and swollen and I get achy," adds Sarah.
It took nearly 7 years till Sarah was finally diagnosed with Sjogren's syndrome at the age of 14.
It's the same disease that has side-lined Venus Williams. Sarah watched as the tennis star talked on Good Morning America.
"Hearing someone else has it also gives you a feeling that you are not alone," says Sarah.
And like Venus says she will do, Sarah has worked hard to overcome obstacles.
After intense physical therapy, she was happy to be able to put her uniform back on and started cheering again. She is hoping Sjogren's doesn't slow her down.
"Right now I am hoping to live as normal a life as possible," says a smiling Sarah.
Sarah takes 11 medications to help with symptoms. She is hoping this awareness will help people get diagnosed quicker.