Showing Seize the Night by Dean Koontz

One by one, the children of Moonlight Bay are disappearing. No one knows if they are dead or alive. Christopher Snow, suffering from the rare disorder xeroderma pigmentosum, has glimpsed the dark and torrid secrets of the small-town community where he has spent his entire life. And only he has the key to the truth - a truth that could only exist in the genetic chaos of Moonlight Bay.