Definition of Overgrowth syndrome

Overgrowth syndrome: One in a group of disorders resulting in overgrowth, as evidenced by unusually large size at birth, excessive postnatal growth, and increased weight, increased length, and/or increased head circumference. There is an increased risk of cancer in a number of the overgrowth syndromes.

The well-recognized overgrowth syndromes include: Wiedemann-Beckwith syndrome; hemihyperplasia; Simpson-Golabi-Behmel syndrome; Perlman syndrome; Sotos syndrome; Weaver syndrome; Bannayan-Riley-Ruvalcaba syndrome; Proteus syndrome; Klippel-Trenaunay syndrome, Parkes Weber syndrome, and Sturge-Weber syndrome; Maffucci syndrome; neurofibromatosis; and fragile X syndrome. Overproduction of growth hormone by the pituitary gland causes overgrowth before adolescence and a distinctive pattern of overgrowth called acromegaly.