Persistent Müllerian Duct Syndrome

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Persistent Müllerian Duct Syndrome (PMDS) is a reproductive disorder in which the uterus and other parts of the female reproductive tract develop in male dogs. An important consequence of this disease is cryptorchidism (undescended testicles), which occurs in ~50% of affected dogs and causes infertility, as well as increased risk for testicular tumors. The external genitalia can be otherwise normal, making it easy to overlook PMDS as the underlying cause of cryptorchidism. Female dogs are not affected by this disease.

Note: Cryptorchidism has many potential causes, of which PMDS is only one.

The genetic mutation that causes PMDS has been reported in miniature schnauzer dogs, and the test that we offer specifically checks for this mutation. We believe that the mutation is relatively common in this breed (~25% carrier rate, ~2% genetically affected). Mutation screening has not been reported in other breeds. However, PMDS has been described in the papillon, Belgian Malinois, Leonberger, Doberman pinscher, basset hound, and English cocker spaniel. It is unknown if these breeds have the same mutation that causes the disorder in miniature schnauzers or if there are distinct mutations present.