Prader Willi Syndrome and Advanced Paternal Age: father was about 52

But Costello, a long-time friend and admirer of de Lone, had agreed to do something to help raise money to battle the incurable condition from which de Lone's 9-year-old son, Richard, suffers, the little-known Prader-Willi syndrome, a chromosome disorder that affects 1 in 15,000 births and leaves its victims perpetually starving. "It's got to be one of the most difficult things any parent could have to deal with," says Costello.

De Lone, 61, would be the guy to pull off an impossible reunion like this because there is nobody more universally liked in Marin County music circles. A utility keyboard player who has led many of his own bands - including the pioneering '70s band, Eggs Over Easy, whose 1971 stint in London is credited with starting that country's pub rock movement - de Lone has long been known as one of the nicest guys anyone could want on the bandstand. Those who have wanted him include Bonnie Raitt, the Fabulous Thunderbirds, Commander Cody, Boz Scaggs, Lightnin' Hopkins and countless others.

Most cases of Prader-Willi syndrome (about 70 percent) occur when a segment of the paternal chromosome 15 is deleted in each cell. It is not inherited but a germ-line mutation. http://ghr.nlm.nih.gov/condition=praderwillisyndrome