PetSavers – Funding the GENetic associations with dilated cardiomyopathy in DEERhounds (GENDEER) Study
17 June 2021
Deerhounds are reported to have a high prevalence of the heart disease dilated cardiomyopathy (DCM). Primary DCM remains an idiopathic disease, but there is growing evidence that, as in humans, canine DCM has a strong genetic basis with marked familial transmission. The main aim of this research project is to identify genetic loci associated with DCM in Deerhounds. The motivation behind it follows an earlier longitudinal study establishing the echocardiographic reference intervals in healthy Deerhounds. This involved scanning numerous Deerhounds at shows around the UK and following them throughout their lives. Not only were the echocardiographic reference intervals for this breed established, but it was calculated that approximately 1 in 5 of apparently clinically healthy Deerhounds were affected with preclinical DCM. In view of the relatively high prevalence of DCM, a study assessing possible genetic mutations leading to DCM in Deerhounds was launched.
Biomarker measurement
The measurement of biomarkers such as N-terminal pro-brain natriuretic peptide (NT-proBNP), in addition to Holter analyses, has been shown to help vets diagnose early (preclinical) DCM in Dobermanns; so it may also be useful in other breeds. Genetic tests would provide additional important information to aid diagnosis. As DCM is an adult-onset disease, testing breeding dogs and bitches, before breeding, for any genetic mutations that could lead to DCM would be helpful in preventing disease. Genetic tests would also aid diagnosis in suspected cases of DCM identified by general practitioner or referral vets. Diagnosing DCM early in the disease process is important as there is evidence from the PROTECT Study1 that treatment in the preclinical stage of DCM prolongs the period before onset of heart failure and extends survival.
For this study, genome-wide association studies (GWAS) will be performed on surplus blood samples collected from DCM-affected Deerhounds and DCM-free, healthy control Deerhounds. All Deerhounds should have undergone an echocardiogram. Clinically healthy Deerhounds will be scanned by the lead investigator at annual breed shows as well as by other cardiologists in practice, including those abroad. Holter monitors are being offered for use in diagnosis and may be applied by the Deerhound’s veterinary practitioner or by the attending cardiologist. At the same time, blood pressure measurements and blood samples to measure T4/TSH (to help exclude hypothyroidism) and cardiac biomarker concentrations will be taken. Surplus blood from collected samples is being stored at the DNA archive in the University of Manchester’s Centre for Integrated Genomic Medical Research awaiting further genetic analysis. The study population selection criteria for DCM-affected Deerhounds are those of any age selected either due to there being a suspicion of heart disease (e.g. the presence of a heart murmur or gallop rhythm picked up at a routine vaccination appointment) or breeding animals whose owners request a blood test for NT-proBNP to help exclude heart disease prior to breeding. Finally, any owners concerned that their pets could have heart disease can request the NT-proBNP test and may be included in the study. All Deerhounds recruited for this study must be pure bred.
Identifying a genetic basis to primary DCM in Deerhounds could help in the discovery of a DNA test for the disease in this breed for use in general practice as well as referral practice. We are very grateful to PetSavers and the Veterinary Cardiovascular Society for their generous funding of this study.
More information can be found at https://www.deerhoundgenetics.com/. For any questions regarding the GENDEER Study, or if you have a case which may be suitable, please email emily@cheshirecardiology.com.