The Bowlin family knew they had a history of malformations in the brain. But they had no idea how far back it went.
Of the three Bowlin sisters, Margaret, the middle one, was the first to show signs. She began having seizures as a toddler. Then the eldest, Bettina, had a brief and mysterious episode of weakness in her right hand. In 1986, as an adult, she had a two-week migraine that got so bad, she couldn’t hold food in her mouth or money in her right hand. The youngest, Susan, felt fine, but her parents still took her for an exam in 1989, when she was 19. A brain scan found abnormal clusters of blood vessels that, as it turned out, were in her sisters’ brains too. These malformations in the brain can be silent. But they can also leak or, worse, burst without warning, causing the seizures, migraines, and strokelike symptoms Bettina and Margaret experienced. If the bleeding in the brain gets bad enough, it can be deadly.