As fraternal twins the two do not have identical DNA, and the Tucker family has no history of strokes in the family.
Kathryn was going to bed in her Tempe, Ariz. apartment when her stroke struck with sharp pain in her right side. Her brother took her to the hospital after she lost her vision and went numb.
Doctors initially wrote her symptoms off as a migraine and sent her home. She "slept for three days straight," she said. When she woke up, her vision was so foggy she could not navigate her apartment.
When her symptoms did not subside, they realized that the 26-year-old was one of the growing number of young people that has had a stroke.
Kimberly Tucker suffered a stroke of her own nine months later to the day. The stroke came on exactly like Kathryn's did, but on her left side. That morning, she had run a 5 kilometer race. She recognized the symptoms her sister described and called 911. She then called Kathryn, who told her to take blood thinners that may have saved her life.
Both twins' strokes affected the part of the brain that sends visual input from the brain to the retinas.
Doctors said that there is no genetic cause for the twins' strokes, despite their similarity. It is even less common for the two since there is no family history for strokes.
One third of stroke victims are younger than 65, and those with family histories are especially predisposed. For the victims under 45, the risk has increased from 14 to 20 percent.
Doctors say the twins' shared traits -- both smokers, migraine sufferers and users of birth control pills -- increased their risk and are linked to many young stroke sufferers. Kathryn was later discovered to have a patent foramen ovale, or a small hole in her heart.
Kimberly was later diagnosed with arrhythmia. Doctors said each of the heart conditions may have contributed to the stroke.
"Don't think you are impervious to stroke," Kimberly said. "We are not guaranteed great health, and we need to take care of our bodies."
After therapy, the girls are close to recovering. Both Kathryn and Kimberly are unable to drive because of lingering vision problems, but have otherwise returned to normal.
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