Pulmonary hypertension is a disease that causes significant reduction in quality of life for dogs and can lead to collapse, respiratory distress and sometimes death. The most commonly used drug to treat pulmonary hypertension in dogs is sildenafil which targets the PDE5A pathway.  Many dogs that receive sildenafil will have marked improvement in quality of life, however some will respond with less improvement and may be better managed by other drugs that work on pathways other than PDE5A.  Our lab discovered that a mutation in the PDE5A gene is associated with a reduced response to sildenafil. Dogs harboring this mutation may benefit from altered drug dosing or selection of a different drug under the consultation of a veterinarian.

Testing Prices:

PDE5A mutation = $60 per dog

Sample Type for Submission:

Acceptable samples include a cheek swab or 1-2 mL whole blood collected in an EDTA tube. If these sample types are unavailable, please reach out to us at cvm-cardiacgenetics@ncsu.edu for more information. Alternative sample types may result in an additional charge.

Explanation of Results:

Two copies of each gene are inherited, one from each parent. Possible results include:

Negative

Negative dogs have two copies of the normal, unmutated gene. Sildenafil at a dose of 1-3 mg/kg/day is demonstrated to work as expected and often elicits improved quality of life for dogs with pulmonary hypertension. However, very importantly, the absence of the mutation is no guarantee of successful medical intervention.

Positive Heterozygous

Dogs that are positive heterozygous for this mutation have only one copy of the mutated gene. These patients have a reduced response to sildenafil as measured by their quality of life after sildenafil therapy.  Compared to dogs without the mutation they respond less favorably to sildenafil and may require alternate drugs that target pathways other than PDE5A or perhaps increased drug dosagesFor further recommendations, please consult with your veterinarian or have your veterinarian reach out to consult Dr. Stern and our NC State Translational Cardiac Genetics and Pharmacogenomics Lab at sternlaboratory@ncsu.edu.

Positive Homozygous

It is rare for dogs to be positive homozygous for this mutation. Those that are positive homozygous are expected to behave similarly to heterozygous individuals with a poor response to sildenafil therapy and little improvement in quality of life. For further recommendations, please consult with your veterinarian or have your veterinarian reach out to consult Dr. Stern and our NC State Translational Cardiac Genetics and Pharmacogenomics Lab at sternlaboratory@ncsu.edu.