Updated

ATP executive chairman and president Brad Drewett announced Tuesday that he is suffering from Motor Neurone Disease (also known as ALS or Lou Gehrig's Disease) and will continue in his current role on an interim basis as the ATP Board of Directors begins the search for his successor.

The 54-year-old Drewett assumed his ATP posts on January 1 of last year.

"It has been a privilege to serve as executive chairman and president of the ATP, an organization that I've been a part of for more than 35 years since I became a professional tennis player," Drewett said. "I hold the ATP very close to my heart, and it's with sadness that I make the decision to enter this transition period due to my ill-health."

Superstar Roger Federer, president of the ATP Player Council, said: "Brad has become a good friend of mine over the years and this is very sad news for all of us at the ATP and the entire tennis community. He is well-liked and respected by everyone and has done a tremendous job in leading the ATP over the past 12 months, overseeing some major initiatives and a record-breaking year in 2012. His dedication and service to the sport over the years has been truly admirable and he has been a central figure in helping to grow the ATP product across the globe. Our thoughts are with him and his family during this difficult time."

Drewett has been part of the ATP for more than 35 years, as a player, ATP Player Council member, ATP Player Board member, as CEO of the International Region, tournament director of the ATP World Tour Finals, and most recently as the ATP executive chairman and president for the last 12 months.

The ATP parted ways with chief executive Adam Helfant at the end of 2011.