Dementia Gene Mutation Identified

(HealthDay News) -- Researchers have discovered a new gene mutation linked to frontotemporal dementia, a disease that affects language abilities and socially appropriate behavior in the people who have it.

Frontotemporal dementia is the second most common form of dementia after Alzheimer's disease.

After a decade of work on the question, researchers at the Regional Neurogenetic Centre in Lamezia Terme, Italy, and the Centre for Research in Neurodegenerative Diseases at the University of Toronto identified the mutation in a gene named progranulin by studying the genealogy of 15 generations of an extended Italian family. Thirty-six members of the family have had frontotemporal dementia. Researchers conducted DNA tests on 70 family members, including 13 with the disease.

The mutation is in a gene on chromosome 17, which leads to a loss of progranulin, a protein growth factor that helps brain cells survive. The mutation limits production of the protein to half the normal amount, because only one copy of the gene is active. While reduced production of progranulin is related to dementia, an excess has been tied to cancer.

The researchers reported finding the mutation in nine of the family members with the disease and in 10 people who were too young to have the disease. They noted that four people who have the disease did not have the mutation, but were descendants of a line of the family in which three generations had frontotemporal dementia, indicating a second possible genetic link.

They also noted that the age at which people with the mutation began to see symptoms of frontotemporal dementia varied between 35 and 78 years old.

The findings are published in the July 10 issue of Neurology.

More information
To learn about frontotemporal dementia, visit the National Institute of Neurological Disorders and Stroke.