Yao Defen, 7-feet-8-inches tall, found dead at the age of 40. SHANGHAI, Dec. 5 (UPI) -- The tallest woman in the world, China's Yao Defen, has died at the age of 40, her family said. The 7-foot-8-inch Yao passed away in the house she shared with her mother in a small village in central Anhui Province, Shanghaiist reported Wednesday. Yao's gigantism was caused by a tumor on her pituitary gland. By the age of 15, she was already over 6 feet tall and her family hoped she would have a successful career as a basketball player but her massive frame made that impossible. Instead, Yao found work in a circus freak show that toured the country. There was no word on the exact cause of Yao's death. A neighbor said her mother found her lying in her bed not breathing..