Wanted

The LUPA project first started working with Great Danes in the UK in 2008. As many people will be aware this project, which is a large consortium of vets and geneticists, was set up with funding from the European Commission in an attempt to identify the genetic mutations responsible for diseases in dogs (www.eurolupa.org). In Great Danes, we were specifically hoping to identify the genetic mutation or mutations responsible for dilated cardiomyopathy in the breed.

Great Danes have long been known to be predisposed to DCM but the information we do know about the disease in this breed is based on a small amount of research. A group in the USA proposed that DCM is inherited in an X-linked recessive fashion – i.e. the disease is much more likely to occur in males, and females are usually carriers. Most reports of Great Danes with DCM suggest that they eventually develop congestive heart failure, where fluid builds up in the body, particularly the lungs, resulting in signs such as coughing, difficulty breathing and problems exercising. Clinical signs of heart failure can be treated but DCM cannot be cured.

DCM can be very difficult to control as it is usually an adult-onset disease – that means that dogs will not develop signs of the disease until they are 6 or even older. To add more confusion and difficulty to the control of the disease, not all dogs with DCM show signs of heart failure, and some can die of other diseases. As you can imagine the owners of these dogs would never know they had a heart problem.

The only way to definitively diagnose a dog with DCM while they are still alive is to do a heart scan. Having a heart murmur, an abnormal heart rhythm or a cough is suggestive but these signs can also be caused by other systemic or heart diseases. Usually your dog will be referred to a specialist cardiologist for this scan.

As it can be difficult to diagnose DCM, many dogs that have the disease are bred from, thinking that they are healthy dogs. This has led to an increasing proportion of the population being affected by the disease. This is turn means that it may be very difficult to reduce the number of animals affected by the disease as it is already widespread.

The LUPA project aimed to identify affected and healthy dogs to be included in a genetic analysis. We therefore started scanning dogs free of charge at the University of Liverpool and collecting DNA samples from them. During our screening we found a much higher number of dogs affected by the disease than we previously thought was the case – about 25% of dogs screened had DCM, even though their owners thought they were completely healthy. We also heard about a lot of Great Danes that were dying suddenly, with no explanation. Finally, we have some evidence to suggest that the disease is NOT X-linked and therefore can occur in both males and females with equal frequency. This has important implications for breeding of dogs, and therefore we need more information in order to be certain of how the disease is inherited.

We recently submitted our blood samples to the LUPA project for genetic analysis, and we are hoping to get some preliminary results soon. We hope that this will eventually lead to a genetic test for DCM, which can be used in young dogs, before they are bred from. In the meantime, we need to identify better ways of deciding which dogs are at risk of, or have DCM.

The Great Dane Breed Council and the Kennel Club Charitable Trust gave researchers at the University of Liverpool more money to continue screening UK Great Danes. We have therefore continued screening Great Danes for free, and we have reduced the age limit for inclusion in the study to 4 years. We are also doing 24 hour ECG monitoring in some dogs – called a Holter monitor. This monitors dogs for abnormal heart rhythms which we think are associated with DCM in UK Great Danes, and might explain the high prevalence of sudden death.

We are still recruiting new dogs to the scheme and we would be delighted to hear from anyone who would be interested in bringing their dog for screening at the university. We would also gladly receive any information (especially pedigrees and DNA samples if available) from dogs with DCM, or those that have died suddenly. We would also really like to know if your dog has had a normal heart scan, as this all adds to our knowledge!

All information gathered is completely confidential and is not shared with third parties. We are simply hoping to build up a better picture of DCM in UK Great Danes and work towards better diagnosis and treatment of the disease, and hopefully reducing the prevalence of the disease over time.

If you would like to get in touch with Hannah Stephenson about DCM and/or the research, she can be contacted on 01517956100 or hmc79@liv.ac.uk.