I had a boyfriend who had this disorder. He keeled over dead at the age of 21. My husband's roomie had this disorder. He lasted until his 30s.
My family has a peculiar case with Marfan Syndrome.
Here's the story: My father and his brother married my mother and her sister (two brothers married two sisters) and each family had six children. My uncle and aunt had six children with Marfan Syndrome and all but one (he's 63 and 6'8" tall) died before their mid-20's. All the children from the union of my mom and dad were unaffected. I'm the tallest in the family at 6'0". We don't understand it.
BTW, you'd easily mistake my surviving cousin for Abe Lincoln, looks just like him.