We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Editorial |

Perspectives on Shared Genetic Contributions for Parkinson Disease and Alzheimer Disease

Walter A. Kukull, PhD
Arch Neurol. 2004;61(7):1007-1008. doi:10.1001/archneur.61.7.1007.
Text Size: A A A
Published online


Determining the occurrence of disease(s) in families is a traditional strategy to begin the study of genetic causation. Typically, as diseases cluster in families, the likelihood of a genetic basis for the disease is thought to increase, assuming, of course, no known common, causative environmental exposure. Family studies have formed the basis for many analytic genetic methods, including association, segregation, and linkage analyses; such studies focus on description, characterization, and identification of potential disease-causing genes. In this issue of the ARCHIVES, Levy et al1 use a basic family history design to describe the occurrence of Alzheimer disease (AD) among the relatives of persons with Parkinson disease (PD) as compared with AD occurrence in relatives of similar persons without PD. Because AD and PD are both neurodegenerative diseases, occurrence of one could possibly predispose family members to occurrence of the other, if similar etiologic disease genes were in play. Specifically, Levy and colleagues used the family history design to test the hypothesis that PD and AD may have "major shared genetic contributions to the etiology," which would result in an excess of AD among probands with PD. Their study includes information about AD occurrence in more than 4800 first-degree relatives of probands with PD and control probands; it is reportedly the largest study yet to address this hypothesis. Levy and colleagues found that the probands with PD showed no significant increased risk of AD compared with the AD risk among control relatives. Further, the relative risk (hazard) estimates were consistently null when stratifying by age at PD onset, by presentation (tremor-dominant or postural instability gait disorder), or by type of first-degree relative (parent or sibling); all risk estimates were also adjusted for sex, education, and ethnicity, and proportional hazards modeling accounted for age at AD onset or censoring. Despite the detailed and complete analytic methods, no significant differences emerged. All right, then; the evidence appears quite convincing! Should we as investigators conclude that genetic, etiologic overlap between AD and PD is nonsignificant and inconsequential?

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview





Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Submit a Comment


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.

See Also...
Articles Related By Topic
Related Collections
PubMed Articles

The Rational Clinical Examination: Evidence-Based Clinical Diagnosis

The Rational Clinical Examination: Evidence-Based Clinical Diagnosis
Make the Diagnosis: Parkinsonism