Evidence for genetic factors in vasovagal syncope
A twin-family study
Citation Manager Formats
Make Comment
See Comments

This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Objective: Vasovagal syncope (VVS) is the most frequent type of syncope and a common differential diagnosis of epilepsy. The role of genetic factors in VVS is debated. We performed a twin-family study to clarify this question and to analyze the putative mode of inheritance.
Methods: Fifty-one same-sex twin pairs where at least 1 had syncope were ascertained. The twins were interviewed via telephone using a standardized questionnaire. Available medical records were obtained. Information on the affected status of first- and second-degree relatives was acquired.
Results: There was a trend toward higher casewise concordance in monozygous (MZ, 0.75) than dizygous (DZ, 0.50) twins for any syncope (p = 0.06). Significant and strong effects on concordance between MZ and DZ twins were found for fainting at least twice unrelated to external circumstances (0.71 vs 0.27, p = 0.018) and for syncope associated with typical vasovagal triggers (0.62 vs 0.00, p < 0.001). Twelve of 19 concordant MZ twin pairs reported sparse or no other affected family members whereas in the other 7 pairs multiple close relatives were affected.
Conclusions: The twin analysis provides strong evidence for the relevance of genetic factors in VVS. Analysis of the families suggests that complex inheritance (multiple genes ± environmental factors) is usual, with rarer families possibly segregating a major autosomal dominant gene.
GLOSSARY
- ATR=
- Australian Twin Registry;
- DZ=
- dizygous;
- MZ=
- monozygous;
- VVS=
- vasovagal syncope
Footnotes
Study funding: Supported by a project grant (ID 509135) and an enabling grant (ID 628911) of the National Health and Medical Research Council of Australia. K.M.K. was supported by a research fellowship from the Deutsche Forschungsgemeinschaft (KL 2254/1-1) and a scholarship from The University of Melbourne.
Supplemental data at www.neurology.org
- Received January 19, 2012.
- Accepted March 19, 2012.
- Copyright © 2012 by AAN Enterprises, Inc.
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
For assistance, please contact:
AAN Members (800) 879-1960 or (612) 928-6000 (International)
Non-AAN Member subscribers (800) 638-3030 or (301) 223-2300 option 3, select 1 (international)
Sign Up
Information on how to subscribe to Neurology and Neurology: Clinical Practice can be found here
Purchase
Individual access to articles is available through the Add to Cart option on the article page. Access for 1 day (from the computer you are currently using) is US$ 39.00. Pay-per-view content is for the use of the payee only, and content may not be further distributed by print or electronic means. The payee may view, download, and/or print the article for his/her personal, scholarly, research, and educational use. Distributing copies (electronic or otherwise) of the article is not allowed.
Disputes & Debates: Rapid online correspondence
NOTE: All authors' disclosures must be entered and current in our database before comments can be posted. Enter and update disclosures at http://submit.neurology.org. Exception: replies to comments concerning an article you originally authored do not require updated disclosures.
- Stay timely. Submit only on articles published within the last 8 weeks.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- 200 words maximum.
- 5 references maximum. Reference 1 must be the article on which you are commenting.
- 5 authors maximum. Exception: replies can include all original authors of the article.
- Submitted comments are subject to editing and editor review prior to posting.