Persistent Müllerian Duct Syndrome

Persistent Müllerian Duct Syndrome (PMDS) is a disorder of sexual development affecting male dogs, where a uterus and other female sex organs develop in otherwise externally normal-appearing male dogs.

Found in

1 in 360 dogs

in our testing

Key Signs

Internal female reproductive organs in externally normal males, Cryptorchidism, Sterility or subfertility, Uterine infections, Sertoli cell tumor

Age of Onset

At birth

Present at birth


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with PMDS

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about PMDS

The males affected with PMDS appear externally normal, but they have a uterus, cervix, part of the vagina, and fallopian tubes. Approximately 50% of PMDS-affected males are cryptorchid (absence of one or both testes from the scrotum). PMDS is characterized by sterility or subfertility, but affected males that are unilateral cryptorchids have sired litters. Aged PMDS dogs may develop pyometra (uterine infection) or a Sertoli cell tumor.

Treatment is surgical removal of any female reproductive organs and retained testes to eliminate the risk of uterine infections or Sertoli cell tumors. It is also recommended that any descended testes be removed to prevent unintended matings that could allow the mutation to be passed on to puppies.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the PMDS mutation can be safely bred with a clear dog with no copies of the PMDS mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the PMDS mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the PMDS mutation could develop due to a different genetic or clinical cause.

Technical Details

Gene AMHR2
Variant C>T
Chromosome 27
Coordinate 1,794,738

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Wu, X., Wan, S., Pujar, S., Haskins, M. E., Donald, H., Lee, M. M., & Meyers-wallen, V. N. (2009). NIH Public Access, 30(1), 46–56. View the article