Below is an extended transcript excerpt from the Autism Now series, edited for length, relevance and clarity, with Dr. Timothy Buie, associate in pediatrics at Massachusetts General Hospital, who examined Robert MacNeil's grandson, Nick, for gastrointestinal problems, and appeared in…

Updated on April 22 with video of sixth and final segment in the series. The PBS NewsHour is launching a special series of reports, both on-air and online, about a puzzling disorder that touches many lives across the U.S.:…