Myxomatous Mitral Valve Disease (MMVD)
Mitral Regurgitation, Degenerative Mitral Valve Disease, Endocardiosis
Myxomatous Mitral Valve Disease (MMVD) is a disease leading to a progressive degenerative change of the heart mitral valve that can lead to fluid accumulation in the lungs and congestive heart failure. The mitral valve is located between the left atrium and the left ventricle and prevents blood flow backward between these two chambers. Dogs that test affected for the MMVD NEBL3 mutation can be subject to mitral valve degeneration which, over time leads to increased growth of the left atrium to accommodate the extra blood and increased pressure. This also causes a back up in the blood returning from the lungs which leads to fluid build up over time which eventually leads to congestive heart failure and difficulty breathing. The condition can be managed in the short term with diuretic medications. It is important to note that MMVD is a complex multifactorial disease and this test should be considered a risk-factor test. The results of this test should not be used to predict or diagnose MMVD but can be useful for making breeding decisions.
Reading Your Results
A. (CLEAR/NORMAL):
These dogs have two copies of the normal gene and will neither develop Myxomatous Mitral Valve Disease nor pass this mutation to their offspring.
B. (CARRIER/NOT AFFECTED):
These dogs have one copy of the normal gene and one copy of the mutation associated with this disease. They will not develop Myxomatous Mitral Valve Disease but will, if bred, pass the mutation to 50% of their offspring, on average.
C. (AT RISK/AFFECTED):
These dogs have two copies of the mutation associated with this disease and are at risk of developing Myxomatous Mitral Valve Disease.
Additional Details
Inheritances
Autosomal Recessive with Incomplete Penetrance
Affected gene
NEBL
OFA Accepted
No
Chromosome
Ch. 2
Mutation
11,979,724 G>A (NEBL3 risk variant)
Publication:
Mead SE, Beijerink NJ, O’Brien M, Wade CM. Genetic Variants at the Nebulette Locus Are Associated with Myxomatous Mitral Valve Disease Severity in Cavalier King Charles Spaniels. Genes. 2022; 13(12):2292. [PubMed: 36553559]