NEW YORK (Reuters Health) - The risk of Alzheimer’s disease (AD) is not increased among relatives of patients with Parkinson’s disease (PD) compared with relatives of controls, a new study indicates. Therefore, these findings do “not support the hypothesis of major shared genetic contributions to the etiology” of these two diseases, according to a report in the July issue of the Archives of Neurology.
In a case-control study, Dr. Karen Marder from Columbia University, New York, and associates examined 487 probands with PD without dementia and 409 matched probands.
The investigators determined disease status in first-degree relatives of probands with PD and control probands using a structured family history interviews. The probands provided family history information on 4819 first-degree relatives older than 30 years of age. Data for 2285 relatives of control probands were also collected.
A diagnosis of AD was reported for 113 first-degree relatives of PD. “The risk of AD was not increased in relatives of patients with PD compared with relatives of controls,” the authors report.
“Similarly, no significantly increased risk of AD was observed when comparing relatives of patients with early onset and late onset PD with relatives of controls,” they add.
“If there were a major shared genetic influence of PD and AD, we would have expected both an increased risk of PD in AD families and an increased risk of AD in PD families,” Dr. Marder told Reuters Health.
“While clearly there is some overlap in some families in which AD and PD coexist, there is probably not a huge overlap,” Dr. Marder continued. “There may however be shared susceptibility genes that may act together with PD or AD specific genes to cause one or the other disorder.”
Source: Arch Neurol 2004;61:1033-1039. [ Google search on this article ]
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