Forbes disease is a glycogen storage disorder referred to as glycogen storage disease Type III. The disorder usually begins in infancy. Individuals with Forbes disease lack the hepatic debrancher enzyme amylo-l,6-glucosidase, which results in abnormal glycogen accumulation in the liver, muscles, and in some cases the heart. They can not convert glycogen to glucose, so they must eat frequently or they will suffer from hypoglycemia. Prominent characteristics in children with this disorder include an enlarged liver (hepatomegaly), unusual body fat distribution, hypotonia, and short stature due to retarded physical growth. After puberty, many individuals have a normal growth spurt, they experience few hypoglycemic episodes, and their liver decreases in size.