Children with Learning Disorders process information differently. Learning Disorders are caused by a faulty brain system, either in the structure of the brain or the functioning of different chemicals. Underlying abnormalities in cognitive processing (e.g., deficits in visual perception, linguistic processes, attention, or memory, or a combination) often precede or are associated with Learning Disorders. Genetic predisposition, perinatal injury, and various neurological or other general medical conditions may be associated with Learning Disorders, but the presence of such conditions does not necessarily predict a Learning Disorder. Learning Disorders are, however, frequently found in association with a variety of general medical conditions (e.g., lead poisoning, fetal alcohol syndrome, or fragile X syndrome).