The Leap Year Boy by Marc Simon
Set in Pittsburgh in the early 1900s, The Leap Year Boy is the story of a working class family and an extraordinary boy named Alex Miller, born in the family's home on February 29, 1908. What makes Alex so remarkable is that even though he's full-term at birth, he weighs just two pounds one ounce, and is nine inches long.
Despite his size, Alex is perfectly healthy. However, his body grows at one-fourth the rate of a normal child--so that after one year, he's the size of a three-month-old--but his mind grows much quicker. Eventually, so do certain parts of his body and his ability to do various and unusual things with them. As Alex's special abilities become apparent, those around him see him as both a miracle child and a freak of nature--a freak to exploit.
How Alex saves himself from the designs of others--his religious fanatic grandmother, who sees him as the new Messiah; his money-grubbing immigrant doctor, who wants to put him on display; his unstable nanny, who believes Alex is her lost child; and his father and father's mistress, who are eager to tap Alex's commercial potential--is at the heart of the novel. Ultimately, a family that has been fractured by ambition and circumstance rediscovers loyalty and love, thanks to Alex's courage.