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What Is Persistent Müllerian Duct Syndrome?

Medically Reviewed by Brunilda Nazario, MD on January 24, 2022

Persistent Müllerian duct syndrome, or PMDS, is a condition in which a biological male develops female sex organs -- specifically a uterus and fallopian tubes -- in addition to male sex organs. Doctors also sometimes call it persistent oviduct syndrome.

What Causes PMDS?

The short answer is your genes.

While in the womb, babies (male or female) grow a Müllerian duct. Normally, as girls grow in the womb, this duct develops into female sex organs. In boys, on the other hand, their genes cause the release of proteins that break down this duct so that it doesn’t develop further.

The genes in developing baby boys with PMDS have changes (mutations) that make these proteins unable to work. As a result, the Müllerian duct continues to develop into a uterus and fallopian tubes that serve no useful biological purpose and may cause health problems.

Who Gets PMDS?

People with PMDS inherit the gene mutations that cause it from their parents. This happens in an “autosomal recessive” pattern. Autosomal means the gene is found in both men and women. Recessive means that both of your parents need to be “carriers” of the mutation for you to get it.

For that to happen, each of your parents must inherit the mutation from one (but not both) of their own parents. (We all carry a full set of genes from both our mother and father.)

Your biological parents won’t have the condition, because you get PMDS only when you inherit the mutations from BOTH parents.

But just because both parents have a copy of the PMDS mutation, it doesn’t mean a child will get it. In general, when a biological mother and father each carry the same autosomal recessive mutation, the chance that a child will inherit the disease-causing mutation is one in four. In addition, though both males and females can inherit the gene mutations that cause PMDS, only biological males have symptoms of the disease.

What Are the Signs and Symptoms of PMDS?

One of the first signs of PMDS in boys (girls don’t get it) is that one or both testes don’t descend. It’s also common to see bulges that poke through the muscles in the groin area (inguinal hernia). But it’s important to remember that these symptoms are far more likely due to some other cause. (PMDS is very rare.)

In children, doctors typically discover PMDS by chance during surgery to correct one or both issues. The surgeon notices a uterus and fallopian tubes (and sometimes other female structures) in unusual positions in the pelvic area. If one testicle has descended, it may pull some of the fallopian tube and uterus with it.

Other possible symptoms of PMDS include:

  • Abnormal growth patterns in internal male genitalia
  • The signs or appearance of external female genitalia in addition to normal male genitalia (male pseudohermaphroditism)
  • Abnormal hormone levels

What Are the Possible Long-Term Effects of PMDS?

Adult males with PMDS may be unable to biologically father children.

Men with PMDS may also notice blood in their semen. They also have a higher risk of testicular cancer. More specifically, undescended testes left untreated may break down and develop cancer.

How Do Doctors Diagnose PMDS?

Doctors often discover PMDS during surgery to correct some of the symptoms of the disease (like hernias or undescended testes). Other possible tools to help diagnose the condition include:

  • A physical exam to check for signs of disease inside or outside the body
  • Imaging studies to look for unusual internal structures or growth patterns
  • Blood tests to check for abnormal hormone levels
  • Genetic testing to check for the mutations that cause PMDS

How Do Doctors Treat PMDS?

The primary treatment is surgery to remove the uterus, fallopian tubes, and any other female structures from the male pelvis. Doctors will also use surgery to correct inguinal hernias and undescended testes.

Later, doctors may be able to help infertile men with PMDS by taking sperm from the testes with a needle to use in assisted reproductive therapy.

A special hormone doctor (endocrinologist) may also help manage or adjust hormone levels.

How Common Is PMDS?

Though it is still unclear exactly how many people have PMDS, it appears to be extremely rare. Scientists have reported at least 250 people with the condition in medical literature.

Show Sources

SOURCES:

Johns Hopkins Medicine: “Inguinal Hernia.”

Human Phenotype Ontology Project: “Male pseudohermaphroditism.”

MedlinePlus Genetics Home Reference: “Persistent Müllerian duct syndrome.”

NIH Genetic and Rare Diseases Information Center (GARD): “Persistent Müllerian duct syndrome.”

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