Serena Williams says her sister Venus Williams’ decision to withdraw from the U.S. Open because of Sjorgen’s Syndrome has given her a little perspective.

The tennis champ, who has had her own health scares recently, tells PEOPLE her sister’s diagnosis made her realize that life “isn’t all about tennis.”

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“I love playing tennis and I love the battle,” she says, “but I realize that life is so precious.”

Serena adds that Venus is in good spirits and she’s staying positive.

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Sjorgen’s Syndrome is an autoimmune disease that causes fatigue and joint pain. Some four millions Americans suffer from the condition.

Get well, Venus!

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