The former Red Sox star and brother to Joe DiMaggio died of undisclosed causes:
http://sports.yahoo.com/mlb/news?slug=ap-obit-domdimaggio&prov=ap&type=lgns
I think those undisclosed causes he died of are called 'living more than 90 years'.
He is the answer to one of my favorite baseball trivia questions: Of the three DiMaggio major leaguers, which is the only one to win the All-Star game MVP?
Interesting bit about the famous Enos Slaughter play, which every Cardinals fan knows, and how Dom figured into it.