Disease overview

Persistent Müllerian duct syndrome (PMDS), also known as persistent oviduct syndrome, is a disorder of sexual development in which the uterus and other parts of the female reproductive tract develop in male dogs. The embryo of a developing fetus is predestined to have a female reproductive tract, which includes the mullerian duct. Without proper stimulation by hormones, dogs that develop into males may retain the mullerian duct, which leads to PMDS. With PMDS, male dogs will have normal male external genitalia, but may have unilateral or bilateral undescended testes (cryptorchidism).

Gene name

AMHR2

Inheritance

Autosomal recessive (sex-limited)

Signs and symptoms

External genitilia in male puppies with PMDS can appear normal, as the majority of the developmental abnormalities are internal. However, approximately 50% of these males will have cryptorchidism, with a higher likelihood of developing testicular tumors or twisting of the reproductive cords (torsion). Testosterone levels will be normal, but these dogs may be infertile as the temperature of the testes is too high for sperm development. Affected dogs may experience uterine lining inflammation (endometritis) or other complications related to the uterus. Clinical signs may include swelling of the abdomen.

How is it diagnosed

A veterinarian will conduct a thorough exam, including a review of health history and any clinical signs. PMDS is typically first noticed during the neutering process, where it becomes apparent that the testes are not present externally. An ultrasound can determine if there is cryptorchidism (testicular retention). Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

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Citations

Wu X, Wan S, Pujar S, Haskins ME, Schlafer DH, Lee MM, Meyers-Wallen VN. A single base pair mutation encoding a premature stop codon in the MIS type II receptor is responsible for canine persistent Müllerian duct syndrome. J Androl. 2009 Jan-Feb;30(1):46-56. doi: 10.2164/jandrol.108.005736. Epub 2008 Aug 21. PMID: 18723470; PMCID: PMC2593750.

De Lorenzi L, Arrighi S, Groppetti D, Bonacina S, Parma P. Persistent Müllerian Duct Syndrome in a German Shepherd Dog. Sex Dev. 2018;12(6):288-294. doi: 10.1159/000492037. Epub 2018 Aug 8. PMID: 30086548.

Nickel RF, Ubbink G, van der Gaag I, van Sluijs FJ. Persistent müllerian duct syndrome in the basset hound. Tijdschr Diergeneeskd. 1992 Apr;117 Suppl 1:31S. PMID: 1585319.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.