Brooke Megan Greenberg (January 8, 1993 – October 24, 2013) was an American who remained physically and cognitively similar to a toddler, despite her increasing age. She was about 30 in (76 cm) tall, weighed about 16 lb (7.3 kg) and had an estimated mental age of nine months to one year. Brooke's doctors termed her condition Syndrome X.

Brooke was born on January 8, 1993 to parents Howard and Melanie Greenberg[4] at Sinai Hospital in Baltimore, Maryland. She was delivered by Caesarean section, one month before her due date due to "intermittent growth",[5] weighing just four pounds (1.8 kg). She was born with anterior hip dislocation, a condition that caused her legs to be swiveled upward toward her shoulders; it was corrected surgically. Otherwise, Brooke appeared to be a normal infant. She had three sisters that were born normal; Emily, Caitlyn and Carly.

She couldn't walk or talk and was fed daily by stomach tube.

Brooke Greenberg died on October 24, 2013, at the Herman and Walter Samuelson Children's Hospital at Sinai Medical Center in Baltimore, the same hospital where she was born. Her funeral service took place on October 27, 2013, and that same morning, she was buried at Baltimore Hebrew Cemetery - Berrymans Lane, in Reisterstown, Maryland.[2] The cause of her death was bronchomalacia, a medical condition usually occurring in children, which results in difficulty breathing due to weak cartilage in the walls of the bronchial tubes.