Unfortunately, FOP does not improve over time. The "P" in FOP stands for "Progressiva." That means that FOP will progress, or get worse, as a person ages. As FOP is part of a person's genetic make-up, people with FOP are born with the condition, even though the extra bone may not have appeared at birth. So people with FOP will not outgrow the condition. Nor can the extra bone that has been produced by FOP disappear. The body of a person with FOP does not make extra bone all of the time; a person with FOP may go months or years without a flare-up. Yet there is always a chance that extra bone can form, either without any warning ("spontaneous flare-up") or following trauma, such as a bump, fall, muscle overexertion, an injury, intramuscular injections, surgery, or even some viruses. It is unclear why the disease is active some times and quiet or dormant at other times.