Is Disorder That Causes Dementia Hereditary?

Main Category: Alzheimer's / Dementia
Also Included In: Neurology / Neuroscience;  Genetics
Article Date: 03 Nov 2009 - 2:00 PST

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New research shows that a rare brain disorder that causes early dementia is highly hereditary. The study is published in the November 3, 2009, issue of Neurology®, the medical journal of the American Academy of Neurology.

The brain disorder, called frontotemporal dementia, is formerly known as Pick's disease and destroys parts of the brain, leading to dementia, including problems with language or changes in behavior and personality. The disease often affects people under the age of 65.

"Knowing your family's health history may be one way for people to better predict their risk of developing dementia," said study author Jonathan Rohrer, MRCP Clinical Research Fellow at the Dementia Research Center at the University College London in the United Kingdom.

For the study, blood was drawn from 225 people who were diagnosed with frontotemporal dementia. The people were asked about family history of dementia and given a score of one through four. A score of one represents a person who had at least three relatives with dementia and an autosomal dominant inheritance, meaning that an affected person has one mutant gene and one normal gene and has a 50-percent chance of passing the mutant gene and therefore the disorder on to their offspring. A score of four represents a person with no family history of dementia.

The study found that nearly 42 percent of participants scored between a one and a 3.5, meaning they had some family history of dementia. However, only 10 percent had an autosomal dominant gene history.

The people in the study also had their DNA tested for five gene mutations thought to cause frontotemporal dementia. Mutations were found in two of the five genes.

"Many people were still found to have a strong family history of dementia even without having any of the five known gene mutations, suggesting that there are still unknown genes that cause frontotemporal dementia," said Rohrer.

"Discovering new genes and gene mutations could provide another key to unlocking the doors to new treatments and prevention strategies for dementia."

The study also found that behavioral problems associated with frontotemporal dementia were the most likely to be hereditary, while language problems were the least likely to be hereditary.

The study is supported by the United Kingdom Department of Health's NIHR Biomedical Research Centers, the Medical Research Council UK and the Alzheimer's Research Trust in the United Kingdom.

November is National Alzheimer's Awareness Month.

The American Academy of Neurology, an association of more than 21,000 neurologists and neuroscience professionals, is dedicated to promoting the highest quality patient-centered neurologic care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as epilepsy, dystonia, migraine, Huntington's disease and dementia.

Source: American Academy of Neurology (AAN)