Childhood illness:

Helen Keller developed an illness when she was nineteen months old. Though she recovered from the illness, it caused her to become totally blind and deaf. These obstacles greatly shaped the person Helen became. It contributed to how she learned, and how she perceived herself and the world around her.

(p. 3-4) The Story of My Life by Helen Keller. Dover Publications, 1996. Originally published by Doubleday, 1903.