Jonathan Boies, a son of renowned trial lawyer David Boies and one of the first hires at the law firm that became Boies Schiller Flexner, died Feb. 22 of complications related to a vascular brain condition. He was 50.

David Boies confirmed his son’s unexpected death in Aventura. Jonathan Boies was visiting for a family birthday celebration. The cause was a rare condition called arteriovenous malformation, an abnormal connection between arteries and veins in the brain.