There is a cardiac arrhythmia specific in GSDS. Dr. Sydney Moise at Cornell University, NY has had a breeding colony of GSDS for years studying this. Parents have to be tested (24 hour holter monitor) as do siblings to determine if they are indeed carriers. She has years of pedigrees showing many of the dogs affected. The last I knew, they were looking for a genetic marker to identify the carriers. The research for SIDS have been very involved as this is similar to what causes sudden death in children. This is listed in our blue book on genetics. Scootie Sherlock could also give you information. Hope this helps, Pat GSRCNY.ORG ============================================================================ POST is Copyrighted 2006. All material remains the property of the original author and of GSD Communication, Inc. NO REPRODUCTIONS or FORWARDS of any kind are permitted without prior permission of the original author AND of the Showgsd-l Management. ALL RIGHTS RESERVED. ALL PERSONS ARE ON NOTICE THAT THE FORWARDING, REPRODUCTION OR USE IN ANY MANNER OF ANY MATERIAL WHICH APPEARS ON SHOWGSD-L WITHOUT THE EXPRESS PERMISSION OF ALL PARTIES TO THE POST AND THE LIST MANAGEMENT IS EXPRESSLY FORBIDDEN, AND IS A VIOLATION OF LAW. VIOLATORS OF THIS PROHIBITION WILL BE PROSECUTED. For assistance, please contact the List Management at admin@xxxxxxxxxxxx VISIT OUR WEBSITE - www.showgsd.org ============================================================================