U.S. President Barack Obama has paid a special tribute to club music icon Frankie Knuckles by penning a letter to his grieving family and friends. The top producer, known as the Godfather of House, died at the age of 59 in his adopted home of Chicago, Illinois on 31 March (14) after suffering complications related to diabetes. Tributes have poured in from musicians including DJ Roger Sanchez, members of rap group Wu-Tang Clan, British DJ Pete Tong and hip-hop star Questlove, and now a note personally sent to Knuckles' loved ones by former Illinois Senator Obama and his wife Michelle has been shared online by his DJ pal David Morales. The letter, which is dated 17 April (14) and signed by both the President and the First Lady, reads: "We were deeply saddened to learn of Frankie's passing, and we extend our heartfelt sympathies as you mourn his loss and reflect upon his life. "Frankie's work helped open minds and bring people together, blending genres to capture our attention and ignite our imaginations. He was a trailblazer in his field, and his legacy lives on in the city of Chicago and on dance floors across the globe. "While he will be dearly missed, we trust Frankie's spirit will remain a guiding force. At this difficult time, please know we are holding you all in our thoughts and prayers." Knuckles' memory has also been honoured by his friend Sir Elton John, who this week (begs21Apr14) announced the establishment of new HIV awareness charity the Frankie Knuckles Fund.