Although most patients with Alzheimer disease appear to have sporadic forms with predisposing environmental factors that are beginning to be discovered, some cases of early-onset Alzheimer disease can be caused by autosomal dominant genes.1 In sporadic Alzheimer disease, head trauma has been suspected to be an environmental trigger, and chronic traumatic brain injury in boxers has been associated with neurologic defects, especially in association with APOE e4 alleles.2 A case of dementia following head trauma was published in the ARCHIVES in 1982,3 which involved a 22-year-old man with head trauma from a motor vehicle crash that had resulted in skull fracture, subdural hematoma, brain contusion, and coma. Substantial improvement occurred, but 8 years later he developed behavior disturbances, followed by cognitive regression and myoclonic activity. The patient's condition gradually worsened and he died at age 38 years. An autopsy showed old traumatic lesions, extensive neuritic plaques, and neurofibrillary tangles typical of Alzheimer disease. Although the article that reported this case was titled "Posttraumatic Premature Alzheimer's Disease," the authors stated that they did not wish to claim a definite relationship between the patient's head trauma and the later development of Alzheimer disease, but rather wanted to revive a controversial concept. In the 15 years since the article was published, the relationship between head trauma and Alzheimer disease has remained controversial. Recently, new information has come to light clarifying the genetic origin of the illness of the patient described above.
Abuelo DN, Walsh A, Seltzer W, Anath U, Ott BR, Geffroy G. Premature Alzheimer Disease Was Not Due to Trauma: Molecular Biology Revises Diagnosis 15 Years After Patient's Autopsy. Arch Neurol. 1998;55(8):1155. doi: