Study Finds Potential Causes Of Young-Onset Dementia

A new Mayo Clinic study found that young-onset dementia often is caused by neurodegenerative or autoimmune/inflammatory conditions, but only rarely by Alzheimer's disease. This differs substantially from the common causes of dementia in older individuals (Alzheimer's disease and other neurodegenerative dementias). These findings will be presented at the American Academy of Neurology Annual Meeting in Chicago on April 15.

Dementia represents a progressive decline in a person's cognitive function that affects the ability to think, speak, reason, remember and move. The most common forms of dementia are Alzheimer's disease, vascular dementia and Lewy body dementia. Approximately 12 in 100,000 people may develop dementia prior to age 45, called young-onset dementia.

"After seeing several patients in their 20s who had graduated from college and were suddenly experiencing severe dementia, I wanted to try to provide answers as to what was causing dementia at such young ages," says Brendan Kelley, M.D., an author of this study and a neurologist at Mayo Clinic.

Dr. Kelley and a team of Mayo Clinic physicians set out to identify the characteristics and causes of dementia prior to age 45. They identified 235 individuals, ages 17 to 45, who previously had normal cognitive function and were evaluated for progressive cognitive decline at Mayo Clinic from 1996 to 2006. In one-third of patients, the dementia was caused by a neurodegenerative disorder such as frontotemporal dementia, Huntington's disease or familial prion disease. However, Alzheimer's disease was an uncommon cause. In 20 percent of patients, young-onset dementia was caused by autoimmune or inflammatory conditions such as multiple sclerosis, autoimmune encephalopathy or neuropsychiatric lupus. According to Dr. Kelley, this is an important finding, because many of these diseases may have specific treatments.

Additionally, 10 percent had metabolic disorders commonly thought to occur mainly in children. In 19 percent of the patients, the cause of young-onset dementia remained unknown despite thorough and exhaustive evaluation.

"This study sheds light on the fact that young people do, in fact, develop dementia, and that there are important differences between the causes of young-onset dementia and the causes of dementia in older individuals," says Dr. Kelley. "However, more research is required to better understand the characteristics and most effective treatments for young patients with dementia."

Brad Bishop is one of the patients who influenced Dr. Kelley to pursue this research. Bishop, age 27, was diagnosed with frontotemporal dementia in 2006. According to his parents, he was an energetic, thoughtful, caring and intelligent young man who graduated from college in 2004 with a double major in business and computers. His symptoms of dementia started around age 21, including withdrawal from people outside his family, inappropriate behavior, poor financial judgment and progressive decline in cognitive function. Now, Bishop needs around-the-clock care as his brain continues to deteriorate.

"We are seeing our son disappear before our eyes, little bit by little bit," says Susan Bishop, his mother. "We'll always hope for a miracle, but realistically we just want Brad to be safe, happy, comfortable and treated with the dignity and respect that he deserves...every day we have with him is a gift."