40 Year Old Child: A New Case – TLC revisits the Williams family in Billings, Montana, whose 8-year-old daughter Gabby suffers a mystery medical condition that slows her rate of aging. The Williams along with a handful of other families are facing the unknown when battling against this bizarre and inexplicable syndrome that affects the growth and overall development of their children, from blindness and deafness to the inability to walk, eat or even speak on their own. Following the everyday lives of these families and the doctors who have dedicated their careers to studying the signs of aging and are determined to find an answer.