In the mid 1980s, Kaplan met David Romanoff, the medical director of the Inglis House—a residential care facility for adults with disabilities. Two residents of the facility were diagnosed with
fibrodysplasia ossificans progressiva (FOP), a very rare medical condition in which the
soft tissue of the body
ossifies, or turns to bone, over time. Romanoff was "grappling" with caring for the patients, and asked Kaplan if he would like to meet them, which he did. This was his first encounter with the disease beyond reading about it. Kaplan stated that his reaction to meeting the young patient was "visceral and immediate", causing him to request a three-year
sabbatical from his work so that he could begin to research FOP. The cause of the disease was traced to a single mutation in the
activin A receptor, type I gene. After the discovery, Kaplan remarked, "It took our team of researchers and collaborators more than 15 years of diligent effort to unravel the genetic cause of FOP, which had been shrouded in mystery for so long." ==POH research==