Yep! Just one, Pál Szekeres:
He has the distinction of being the first person to have won medals at both the Olympic and Paralympic Games
Szekeres represented Hungary at the 1988 Summer Olympics in Seoul, and won a bronze medal in the team foil event.
In 1991, he was injured in a bus accident, and used a wheelchair. He then took to wheelchair fencing. Described as "the most successful Paralympic athlete in Hungary", he won a gold medal in foil at the 1992 Summer Paralympics in Barcelona, two gold at the 1996 Games in Atlanta, a bronze in 2000, 2004, and 2008.
More info in: List of athletes who have competed in the Paralympics and Olympics → Olympic and Paralympic medal winners:
There is at present only one athlete who has won a medal at the Olympics prior to becoming disabled, and has then gone on to win medals at the Paralympics. Hungarian fencer Pál Szekeres won a bronze medal at the 1988 Summer Olympics, then was disabled in a bus accident, and went on to win three gold medals and three bronze in wheelchair fencing at the Paralympics.
In 2012, Craig MacLean, a British track cyclist and Olympic silver medalist was the sighted pilot for Anthony Kappes as they won gold in the 2012 Paralympic Games. For the first time in those games, the sighted guides of blind athletes were also awarded medals, and MacLean, although not himself disabled, became only the second athlete to win medals in both the Olympic and Paralympic Games.
Swimmer Terence Parkin won a silver in the 200-meter breaststoke in Sydney in 2000, and two gold medals at the Deaflympics in 2005.