Melbourne, Australia –  Former world No. 1 Venus Williams will miss the 2012 Australian Open because of health reasons.

The seven-time Grand Slam champion has been receiving treatment for Sjogren's syndrome, an autoimmune disease that causes fatigue and joint pain. She missed most of the 2011 season while battling the condition, as well as injuries.

Williams said on her website that she plans to return to action next month.

"I regret to announce that I am withdrawing from the 2012 Australian Open," Williams said.

"After several months of training and treatment, I am making steady progress to top competitive form.

"My diet and fitness regimen have allowed me to make great strides in terms of my health and I am very close to being ready to return to WTA competition. I have every intention to return to the circuit in February."

The 31-year-old American star pulled out of her second-round match at the U.S. Open last summer, citing Sjogren's.

Williams, a five-time Wimbledon champ and former Aussie Open runner-up currently ranked 100th in the world, said she hoped to return to the WTA full-time in 2012.

The Aussie Open will get underway next Monday in Melbourne.