🔗

Mappings

MONDO

MONDO:0009857 persistent Mullerian duct syndrome

Primary MONDO identifier for the disease.

👪

Inheritance

1

Autosomal recessive HP:0000007

Affected individuals carry biallelic (homozygous or compound heterozygous) loss-of-function variants in AMH or AMHR2. Heterozygous carriers are unaffected.

Autosomal recessive inheritance

Show evidence (2 references)

PMID:8872466 SUPPORT Human Clinical

"All AMH and AMH receptor mutations were consistent with an autosomal recessive mode of transmission."

A 38-family molecular series states the inheritance mode directly for both the ligand and the receptor gene.

PMID:35052499 SUPPORT Human Clinical

"Persistent Müllerian duct syndrome (PMDS) is a rare autosomal recessive disorder of sexual development in males, defined by the presence of Müllerian remnants with otherwise normal sexual differentiation."

An exome-sequencing case series restates autosomal recessive inheritance alongside the defining internal/external discordance.

◆

Subtypes

2

PMDS type I (AMH ligand deficiency) NCIT:C120189

AMH hgnc:464

PMDS caused by biallelic loss-of-function variants in AMH, the gene encoding the anti-Mullerian hormone ligand. Because the ligand itself is absent or non-functional, serum AMH is low or undetectable, which distinguishes type I from type II biochemically. The clinical picture is otherwise indistinguishable from type II.

Show evidence (1 reference)

PMID:8872466 SUPPORT Human Clinical

"The type of genetic defect could be predicted from the level of serum AMH which is very low or undetectable in patients with AMH mutations and at the upper limit of normal in receptor mutations."

Establishes the ligand-versus-receptor split and the serum AMH measurement that separates the two subtypes.

PMDS type II (AMHR2 receptor defect) NCIT:C120190

AMHR2 hgnc:465

PMDS caused by biallelic loss-of-function variants in AMHR2, the gene encoding the AMH type II receptor. The ligand is made normally but the target tissue cannot respond, so serum AMH is normal or elevated for age. A 27-bp deletion in the kinase domain is the single most common allele, concentrated in individuals of northern European ancestry.

Show evidence (2 references)

PMID:17161334 SUPPORT Human Clinical

"Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."

States the receptor-subtype serum AMH pattern that defines type II against type I. ("AMH type II mutations" here means AMH receptor type II mutations.)

PMID:32172781 SUPPORT Human Clinical

"The most common mutation, a 27-bp deletion in the kinase domain, was found in 30 patients of mostly Northern European origin."

Documents the recurrent AMHR2 kinase-domain deletion and its ancestry distribution.

?

Discussions and Knowledge Gaps

1

Does the mouse AMH-pathway knockout, which retains Mullerian derivatives without the cryptorchidism that dominates human PMDS, model the mechanical tethering step at all?

HUMAN MODEL MISMATCH pmds_mouse_model_lacks_descent_phenotype

Attached to

pathophysiology#Mechanical Tethering of the Testis by Retained Mullerian Structures

The Amh-null and Amhr2-null mouse faithfully reproduces the retained uterus and oviducts, but mouse testes are not scrotal on the human schedule and the knockouts are not reported as cryptorchid. The single most clinically consequential step in human PMDS - the retained structures physically preventing testicular descent, and thereby generating the cryptorchidism, hernia, ectopia, malignancy risk and infertility that bring patients to surgery - is therefore not observable in the standard rodent model. The human evidence for it is inference from operative anatomy rather than experiment. The dog, in which spontaneous AMHR2-related PMDS does present with undescended testes, is the better model for this specific step.

Proposed experiments

Comparative gubernacular and descent phenotyping in canine AMHR2-related PMDS

canine_amhr2_descent_phenotyping

Characterize gubernacular attachment, cord anatomy and testicular position in dogs with naturally occurring AMHR2-related PMDS against unaffected littermates, to test whether the retained Mullerian structures are the physical constraint on descent rather than a co-occurring finding.

Readouts

Testicular position relative to the inguinal ring

pathophysiology#Mechanical Tethering of the Testis by Retained Mullerian Structures

Direction: ALTERED

Interpretation: A tether-dependent constraint predicts that testicular position tracks the extent and attachment of the retained structures.

⚙

Pathophysiology

10

AMH Ligand or AMHR2 Receptor Loss of Function

Biallelic loss-of-function variants abolish either the anti-Mullerian hormone ligand secreted by fetal Sertoli cells (type I) or the type II serine/threonine kinase receptor AMHR2 that receives it (type II). About 12 percent of clinically diagnosed cases carry no identified variant in either gene, implying at least one further pathway component.

fetal Sertoli cell CL:0000216

AMH hgnc:464 AMHR2 hgnc:465

anti-Mullerian hormone receptor activity GO:1990272 ⇓ LOSS OF FUNCTION

Downstream

Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme Absent ligand or a non-functional receptor removes the input to the AMH signaling cascade in the target mesenchyme.

Show evidence (2 references)

PMID:31301298 SUPPORT Human Clinical

"AMH is expressed in Sertoli cells of the fetal and adult testes and granulosa cells of the postnatal ovary."

Locates AMH production in fetal Sertoli cells, the cell type annotated on this node.

PMID:32172781 SUPPORT Human Clinical

"In 12% of cases, no mutation of AMH or AMHR2 has been detected, suggesting a disruption of other pathways involved in Müllerian regression."

Supports the statement that a minority of cases have variants in neither gene.

Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme

AMHR2 is expressed on the mesenchyme surrounding the Mullerian duct epithelium. Ligand binding to AMHR2 recruits a shared type I BMP receptor (BMPR1A/ALK3, with ACVR1 also implicated) and activates receptor-regulated SMADs. Loss of ligand or receptor collapses the whole cascade at its first step, so the downstream SMAD-dependent transcriptional program that dismantles the duct is never run.

Mullerian duct mesenchymal cell CL:0008019

anti-Mullerian hormone receptor signaling pathway GO:1990262 ⇓ LOSS OF FUNCTION SMAD protein signal transduction GO:0060395 ↓ DECREASED

Animal models

Mullerian-mesenchyme-specific Bmpr1a conditional knockout mouse Mouse recapitulates Tissue-specific deletion isolates the type I receptor requirement within the periductal mesenchyme.

Downstream

Failure of Mullerian Duct Regression Without receptor-complex activation and SMAD signaling in the periductal mesenchyme, the duct is not induced to regress.

Show evidence (3 references)

PMID:31301298 SUPPORT Human Clinical

"AMHR2 is expressed in mesenchyme adjacent to the Müllerian ducts, and in Sertoli, Leydig, and granulosa cells."

Places the receptor on the periductal mesenchyme, the cell type annotated on this node.

PMID:17161334 SUPPORT Human Clinical

"Like other members of the transforming growth factor beta (TGF-beta) family, AMH signals through two serine/threonine kinase receptors, of which type II is specific, and type I is shared with the bone morphogenetic protein family."

Supports the two-receptor architecture, with a ligand-specific type II receptor recruiting a shared type I receptor.

PMID:18391537 SUPPORT Model Organism

"Besides AMH and its specific type II receptor AMHR2 two different type I receptors as well as different SMAD family members have been shown to be involved in the AMH signaling cascade."

Supports SMAD family involvement downstream of AMHR2, the second process annotated on this node.

Failure of Mullerian Duct Regression

Mullerian duct regression is a developmentally scheduled event confined to a narrow window of male fetal differentiation; AMH signaling is required during that window and cannot act later. When the signal fails, the ducts are not dismantled and differentiate along their default path into uterus, Fallopian tubes, and upper vagina.

Mullerian duct regression GO:0001880 ∅ ABSENT

Mullerian duct UBERON:0003890

Animal models

Amhr2 (MIS type II receptor) mutant mouse Mouse recapitulates Genetic ablation of the AMH type II receptor in the mouse reproduces retention of uterus and oviducts in an otherwise male animal.

Downstream

Presence of Uterus in 46,XY Individual The unregressed ducts differentiate into uterus, Fallopian tubes and upper vagina.

Mechanical Tethering of the Testis by Retained Mullerian Structures The persisting duct derivatives are physically continuous with the testis and its cord structures.

Neoplastic Transformation of Retained Mullerian Epithelium Retained Mullerian epithelium persists lifelong and is at risk of malignant change, though far less often than the malpositioned testes.

Show evidence (1 reference)

PMID:17161334 SUPPORT Human Clinical

"Anti-Müllerian hormone (AMH), produced by gonadal somatic cells, is mainly responsible for the regression of Müllerian ducts--the anlagen of uterus and Fallopian tubes--during male sex differentiation."

Identifies Mullerian duct regression as the AMH-dependent process, and the uterus and Fallopian tubes as the structures at stake.

Preserved Leydig Cell Androgen Production and Signaling

AMH and testosterone are two independent arms of male differentiation with different sources and different targets. PMDS breaks only the AMH arm. Leydig cells, testosterone biosynthesis, and androgen receptor signaling are all intact, which is why this is a dissociation and not a global failure of masculinization.

Leydig cell CL:0000178

testosterone biosynthetic process GO:0061370 androgen receptor signaling pathway GO:0030521

Downstream

Normal Wolffian Duct Development and Male External Virilization Intact fetal testosterone maintains the Wolffian ducts and drives external genital masculinization.

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"Male sex differentiation is driven by two hormones, testosterone and anti-Müllerian hormone (AMH), responsible for regression of Müllerian ducts in male fetuses."

Establishes the two-hormone architecture in which only the AMH arm is broken in PMDS.

PMID:35386545 SUPPORT Human Clinical

"In addition, the presence of Leydig cells results in the secretion of testosterone, which directs localised differentiation of Wolffian duct structures including the epididymis, vas deferens, seminal vesicles, and ejaculatory ducts."

Names Leydig-cell testosterone as the driver of Wolffian development, the preserved arm annotated on this node.

Normal Wolffian Duct Development and Male External Virilization

Epididymis, vas deferens, seminal vesicles and ejaculatory ducts form normally, the external genitalia are unambiguously male, and pubertal virilization proceeds. This is the feature that distinguishes PMDS from gonadal dysgenesis and from androgen-pathway disorders of sex development, in which external masculinization is incomplete.

male genitalia development GO:0030539 mesonephric duct development GO:0072177

Downstream

Delayed and Incidental Diagnosis Because nothing about the external phenotype is atypical, there is no prompt to look for internal Mullerian structures.

Show evidence (2 references)

PMID:31301298 SUPPORT Human Clinical

"AMH or AMHR2 mutations in mammals lead to the development of Persistent Müllerian Duct Syndrome (PMDS), a recessive condition in which affected males are fully virilized but retain Müllerian duct-derived tissues, including a uterus and oviducts, and in human and dog, undescended testes."

States the dissociation directly: full virilization alongside retained Mullerian derivatives.

PMID:27329391 SUPPORT Human Clinical

"All patients were genotypically male."

Confirms the 46,XY genotype across a 27-patient surgical series, so the retained structures are not a chromosomal sex discordance.

Mechanical Tethering of the Testis by Retained Mullerian Structures

The retained uterus and Fallopian tubes are anatomically continuous with the testis and its cord, and the vasa deferentia run in the wall of the retained structures. This attachment physically restrains testicular descent, which is why cryptorchidism, hernia uteri inguinale and transverse testicular ectopia are the presenting findings rather than incidental co-occurrences.

Mullerian duct UBERON:0003890

Animal models

Canine AMHR2 p.Arg81Ter Miniature Schnauzer (naturally occurring PMDS) Dog partially recapitulates Affected dogs carry the retained Mullerian derivatives and, unlike the Amh-null and Amhr2-null mouse, present with cryptorchidism, so retention and failed descent co-occur in one animal as they do in human PMDS.

Downstream

Cryptorchidism The tethered testis cannot complete its descent into the scrotum.

Ectopic Testis The same tether can carry a testis across the midline into the contralateral inguinal canal or hemiscrotum.

Inguinal Hernia Mullerian structures and the tethered testis herniate through the inguinal canal, the classic hernia uteri inguinale presentation.

Germ Cell Neoplasia Risk in the Malpositioned Testis Chronic intra-abdominal or ectopic testicular position is the intermediate that raises germ cell tumour risk.

Impaired Spermatogenesis and Excurrent Duct Compromise Malposition, distortion of the excurrent ducts, and surgical injury during repair together degrade spermatogenesis and sperm transport.

Show evidence (2 references)

PMID:35052499 SUPPORT Human Clinical

"The Müllerian duct is attached to the testicles and prevents them from descending to the scrotum from the inguinal rings."

States the attachment and its mechanical consequence, which is the claim of this node.

PMID:35386545 SUPPORT Human Clinical

"Vasa deferentia were clearly identified in close association with the fallopian-tube like structures"

Records the operative finding that the vasa run in intimate association with the retained Mullerian structures.

Germ Cell Neoplasia Risk in the Malpositioned Testis

Undescended and ectopic testes in PMDS carry the elevated germ cell tumour risk of cryptorchid gonads generally. Reported rates vary widely with ascertainment, from roughly 5-18 percent in surgical series to 33 percent among adults in a large referral review; seminoma is the commonest histology. Early orchidopexy is the intervention that addresses it.

Downstream

Testicular Neoplasm

Show evidence (1 reference)

PMID:35386545 SUPPORT Human Clinical

"The reported incidence of malignant change in the testes in PMDS generally ranges from 5 to 18%, a rate which is similar to abdominal undescended testes in men without PMDS."

Gives the lower published range and, importantly, attributes the risk to testicular malposition rather than to PMDS-specific biology.

Neoplastic Transformation of Retained Mullerian Epithelium

The retained uterus and Fallopian tubes remain in situ for life if not excised, and their epithelium can undergo malignant transformation. Adenocarcinoma (including clear-cell and endocervical-type) and adenosarcoma have been reported. This is substantially rarer than testicular malignancy and is the argument for either excision or lifelong imaging surveillance of a preserved remnant.

Downstream

Uterine Neoplasm

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"Cancer of Müllerian derivatives is less frequent."

Supports the claim that Mullerian remnant malignancy occurs but is rarer than testicular malignancy.

PMID:35386545 SUPPORT Human Clinical

"The rate of Müllerian malignancy in the literature ranges from 3.1% to 8.4%"

Gives the reported rate range for malignancy arising in the retained Mullerian structures.

Impaired Spermatogenesis and Excurrent Duct Compromise

Fertility is impaired through several converging routes: prolonged cryptorchidism damages the germinal epithelium, the excurrent ducts are distorted or detached from the testis, and excision of Mullerian remnants can injure the vasa deferentia and their blood supply. Because the last of these is iatrogenic, the surgical strategy chosen has a direct bearing on reproductive outcome.

Downstream

Azoospermia

Male Infertility

Show evidence (2 references)

PMID:9187705 SUPPORT Human Clinical

"Surgical excision of the infantile uterus and fallopian tubes risks damage to vasa deferentia and the deferential blood supply to the testis."

Identifies the iatrogenic route to excurrent duct compromise named in this node.

PMID:35386545 SUPPORT Human Clinical

"It is not clear what contributes, and to what degree, to the reported fertility impairment—it may be due to uncorrected cryptorchidism, or due to coexisting congenital gonadal and Wolffian duct anomalies, or due to ischemic and structural damage to the vas and testis secondary to excision of..."

Enumerates the same converging routes and records that their relative contributions are not established.

Delayed and Incidental Diagnosis

Because external anatomy is normal, PMDS is usually discovered when a surgeon opens the inguinal canal or abdomen for something else: hernia repair, orchidopexy, or laparoscopy for impalpable testes. The consequence is repeated operations before the condition is recognized, and adult presentations with infertility or a tumour.

Show evidence (2 references)

PMID:27329391 SUPPORT Human Clinical

"In 21 patients, the diagnosis was made incidentally while operating for UDT and inguinal hernia."

Quantifies incidental intraoperative diagnosis in 21 of 27 patients in a 24-year multicentre series.

PMID:39682529 SUPPORT Human Clinical

"A high degree of suspicion and awareness is needed to diagnose this condition in order to avoid iterative surgery."

Records the clinical cost of delayed recognition, namely repeated operations.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

10

Digestive 1

Inguinal Hernia FREQUENT HP:0000023

Show evidence (2 references)

PMID:26246705 SUPPORT Human Clinical

"We encountered on the same day in the operation theatre two phenotypic males aged 40 years and 10 months who had inguinal hernia on one side along with contralateral undescended testis."

Two cases with the classic ipsilateral hernia plus contralateral undescended testis configuration.

PMID:35386545 SUPPORT Human Clinical

"HUI usually presents with an ipsilateral hernia with ipsilateral descended testis and Müllerian structures within the hernia."

Describes the hernia uteri inguinale variant and the Mullerian content of the sac.

Genitourinary 8

Presence of Uterus in 46,XY Individual OBLIGATE HP:0034546

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"A Müllerian structure resembling a uterus with bilateral fallopian tube-like structures was seen in the pelvis, along with bilateral intra-abdominal testes."

Direct operative observation of the retained uterus and tubes alongside normal testes.

PMID:39682529 SUPPORT Human Clinical

"characterized by the persistence of Müllerian derivatives, the uterus and/or fallopian tubes, in otherwise normally virilized boys"

States that uterus and/or Fallopian tubes are the persisting derivatives defining the condition.

Cryptorchidism VERY_FREQUENT HP:0000028

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"PMDS can present in one of three ways: bilateral cryptorchidism, unilateral cryptorchidism with contralateral hernia and transverse testicular ectopia."

Names cryptorchidism, in two of its three configurations, as the presenting picture in a review of 157 personal plus published cases.

PMID:27329391 SUPPORT Human Clinical

"Ten patients presented with isolated bilateral UDT, six patients with bilateral UDT and unilateral inguinal hernia (4 left and 2 right sided inguinal hernia), and eight patients presented with right inguinal hernia and left sided UDT."

Documents undescended testes in 24 of 27 patients in a multicentre surgical series.

Ectopic Testis OCCASIONAL HP:6000460

Show evidence (2 references)

PMID:33532339 SUPPORT Human Clinical

"Transverse testicular ectopia (TTE) associated with persistent Mullerian duct syndrome (PMDS) is a rare form of male pseudohermaphroditism usually unexpectedly found at surgery for cryptorchidism or inguinal hernia in children."

Establishes transverse testicular ectopia as a recognized PMDS presentation, typically found intraoperatively.

PMID:27329391 SUPPORT Human Clinical

"In 6 patients (male type), the PMDS was associated with transverse testicular ectopia."

Gives the frequency of transverse testicular ectopia in a 27-patient series, supporting an occasional rather than typical finding.

Male Infertility FREQUENT HP:0003251

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."

States that fertility is rare and conditional, supporting infertility as a frequent but not obligate feature.

PMID:35386545 SUPPORT Human Clinical

"there are reports of fertility and paternity in men with PMDS, including in FT PMDS"

Records documented exceptions to the general fertility impairment, which is why infertility is not curated as obligate.

Azoospermia OCCASIONAL HP:0000027

Show evidence (2 references)

PMID:33532339 SUPPORT Human Clinical

"Semen analysis showed both patients were azoospermic."

Semen analysis in two adult PMDS cases presenting with infertility.

PMID:35052499 SUPPORT Human Clinical

"All three patients were admitted due to azoospermia- and oligospermia-caused infertility."

Three molecularly confirmed adults ascertained through azoospermia or oligospermia.

Testicular Neoplasm OCCASIONAL HP:0010788

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"Testicular malignant degeneration occurs in 33% of adults with PMDS."

The upper reported figure, from a review covering 157 personal cases.

PMID:35386545 SUPPORT Human Clinical

"Seminomas are most commonly recorded, but other Germ cell neoplasia in situ- (GCNIS-) derived testicular tumours are also reported"

Identifies seminoma as the predominant histology, supporting the germ cell characterization.

Uterine Neoplasm VERY_RARE HP:0010784

Show evidence (2 references)

PMID:12218580 SUPPORT Human Clinical

"We report a case of a 67-year-old man with clear cell adenocarcinoma of the remnant uterus in persistent Müllerian duct syndrome."

A clear cell adenocarcinoma arising in the retained uterus.

PMID:16009404 SUPPORT Human Clinical

"We report the case of a 39-year-old man with this syndrome in association with adenocarcinoma from the retained müllerian remnants of probable endocervical origin."

A second, histologically different malignancy in the retained remnant.

Testicular Atrophy Decreased testicular size HP:0008734

No frequency is recorded. The cached sources document the finding in individual patients but none reports a proportion, and a frequency band is a separate quantitative claim that would need its own evidence.

Show evidence (2 references)

PMID:39682529 SUPPORT Human Clinical

"In September 2021, at the age of 12, surgery was repeated on the left hemiscrotum, and a small atrophic left testicle was discovered, for which an orchidectomy was performed, taking into account the risk of malignancy."

An atrophic testis found at a repeat operation in a PMDS patient, and the consequence it carried.

PMID:39682529 SUPPORT Human Clinical

"Pelvic MRI revealed an intrabdominal, hypoplastic right testis and another structure, situated in the left paramedian retrovesical area, resembling an atrophic testis."

Hypoplasia and atrophy of the malpositioned testes documented on imaging in the same patient at first presentation.

Other 1

Normal Male External Genitalia OBLIGATE

Show evidence (2 references)

PMID:39682529 SUPPORT Human Clinical

"On clinical examination, the external genital organs had a male phenotype, with a stretched penile length within age-appropriate limits and a normally located external urethral meatus."

Records the examination finding of normal male external genitalia in a genetically confirmed AMHR2 case.

PMID:35386545 SUPPORT Human Clinical

"On examination, he was noted to have a normal penis with complete prepuce and glanular urethral meatus."

A second independent case records the same normal external examination.

🧬

Genetic Associations

4

AMH

Gene: AMH hgnc:464 relationship_type: CAUSATIVE

Autosomal recessive

Show evidence (2 references)

PMID:32172781 SUPPORT Human Clinical

"Up to January 2019, 81 families with 65 different mutations of the AMH gene, mostly in exons 1, 2 and 5, have been identified."

Documents the AMH allelic spectrum and its exon distribution.

PMID:35052499 SUPPORT Human Clinical

"Case 1 carried a homozygous 4-bp deletion; c.321_324del:p.Q109Lfs*29 in exon 1 of AMH (NM_000479 transcript), which is a frameshift mutation, leading to the loss of function of AMH."

A specific biallelic loss-of-function AMH variant in a molecularly diagnosed PMDS patient.

AMHR2

Gene: AMHR2 hgnc:465 relationship_type: CAUSATIVE

Autosomal recessive

Show evidence (3 references)

PMID:32172781 SUPPORT Human Clinical

"AMHR2 gene mutations comprising 64 different alleles have been discovered in 79 families."

Documents the AMHR2 allelic spectrum across reported families.

PMID:8872466 SUPPORT Human Clinical

"Whereas AMH mutations are extremely diverse, patients from 10 out of 16 families with receptor mutations had a 27 bp deletion in exon 10 on at least one allele."

Establishes the recurrent 27-bp kinase-domain deletion as the commonest receptor allele.

PMID:32187366 SUPPORT Human Clinical

"The patient's paternal allele carried a stop mutation, which was initially thought to be homozygous by Sanger sequencing."

Documents the specific diagnostic pitfall in which an AMHR2 whole-gene deletion in trans makes a point variant appear homozygous.

Unexplained PMDS (no AMH or AMHR2 variant identified)

relationship_type: UNKNOWN

Show evidence (1 reference)

PMID:32172781 SUPPORT Human Clinical

"In 12% of cases, no mutation of AMH or AMHR2 has been detected, suggesting a disruption of other pathways involved in Müllerian regression."

Quantifies the molecularly unexplained fraction and draws the same inference about additional pathway components.

PPP1R12A (Reported candidate gene for molecularly unexplained PMDS; truncating variants found in patients but not yet functionally validated or classified for gene-disease validity.)

Gene: PPP1R12A hgnc:7618 relationship_type: UNKNOWN

Show evidence (5 references)

PMID:36331510 SUPPORT Human Clinical

"Five patients out of 24 (21%) harbored deleterious truncation mutations of PP1R12A, the gene coding for the regulatory subunit of myosin phosphatase, were detected."

The primary human finding: truncating variants in five of twenty-four patients screened after AMH and AMHR2 had been excluded. (The source's typographical "PP1R12A" and its non-agreeing sentence are reproduced verbatim.)

PMID:36331510 SUPPORT Human Clinical

"In addition to PMDS, three of these patients presented with ileal and one with esophageal atresia."

The associated malformations that the authors use to argue the finding is not chance, since they are not seen with AMH or AMHR2 variants.

PMID:36331510 SUPPORT Human Clinical

"The main limitation of the study is the lack of experimental validation of the role of PPP1R12A in Müllerian regression."

The authors' own statement of the limitation, which is why this record is typed UNKNOWN rather than CAUSATIVE.

+ 2 more references

💊

Medical Actions

9

Orchidopexy

Category: Therapeutic Action: Orchiopexy NCIT:C111066

Platform: Surgery

Placement of the malpositioned testes into the scrotum, staged (Fowler-Stephens) when the gonadal vessels are too short. Performed early in childhood, this is the intervention that addresses both fertility potential and germ cell tumour risk, and it takes priority over management of the Mullerian remnant.

Mechanism Target:

Mechanical Tethering of the Testis by Retained Mullerian Structures — Surgical mobilization overcomes the mechanical restraint the retained structures impose on descent.

Show evidence (1 reference)

PMID:35386545 SUPPORT Human Clinical

"Both intra-abdominal testes were successfully moved to an intrascrotal position with the vasa and vasal blood supply intact."

Shows the operation achieving intrascrotal placement despite the tether, which is the mechanism this treatment targets.

Germ Cell Neoplasia Risk in the Malpositioned Testis — Bringing the testis to a palpable scrotal position reduces malignancy risk and makes surveillance by examination possible.

Show evidence (1 reference)

PMID:35386545 SUPPORT Human Clinical

"Early orchidopexy should be offered to children with PMDS."

Recommends early orchidopexy for PMDS specifically, on the malignancy risk-reduction rationale this mechanism link asserts.

Show evidence (1 reference)

PMID:9187705 SUPPORT Human Clinical

"Optimal surgical management is orchiopexy leaving the uterus and fallopian tubes in situ."

Names orchidopexy as the primary operation in a comprehensive review of PMDS surgical management.

Preservation of Mullerian Remnants and the Vas Deferens

Category: Therapeutic Action: Mullerian-remnant-sparing surgical technique Ontology label: Surgical Procedure NCIT:C15329

Platform: Surgery

The vasa deferentia and their blood supply run in the wall of the retained Mullerian structures, so aggressive excision of the remnant risks sterilizing the patient and devascularizing the testis. The recommended default is therefore to leave the uterus and tubes in situ, or to split the remnant sagittally to gain length for descent, rather than to excise it. This trades a small ongoing malignancy risk in the remnant, managed by surveillance, against a large and immediate iatrogenic fertility risk. Where excision is unavoidable, subtotal hysterectomy with deliberate preservation of the vasa is the compromise.

Mechanism Target:

Impaired Spermatogenesis and Excurrent Duct Compromise — Sparing the remnant avoids the iatrogenic component of excurrent duct and testicular vascular injury.

Show evidence (1 reference)

PMID:9187705 SUPPORT Human Clinical

"Surgical excision of persistent müllerian duct structure may result in ischemic and/or traumatic damage to the vasa deferentia and testes."

States the specific harm the sparing technique is designed to avoid, which is the mechanism this treatment targets.

Show evidence (3 references)

PMID:9187705 SUPPORT Human Clinical

"Meticulous proximal salpingectomy and hysterectomy is indicated only in patients whose müllerian structures limit intrascrotal placement of the tests."

Restricts excision to the case where the remnant blocks descent, establishing preservation as the default. (The source's typographical "tests" for "testes" is reproduced verbatim.)

PMID:35386545 SUPPORT Human Clinical

"The Müllerian remnant was preserved to maintain testicular vascularity."

A worked case in which the remnant was deliberately left in situ for vascular preservation.

PMID:26246705 SUPPORT Human Clinical

"Both patients intraoperatively had uterus with fallopian tubes and underwent subtotal hysterectomy with preservation of vas."

Illustrates the subtotal-excision compromise, in which the vas is deliberately spared.

Excision of Mullerian Remnants

Category: Therapeutic Action: Hysterectomy with proximal salpingectomy of Mullerian remnants Ontology label: Hysterectomy NCIT:C15256

Platform: Surgery

Hysterectomy with proximal salpingectomy, removing the retained structures. Reserved for cases where the remnant prevents intrascrotal placement of the testis, or is symptomatic, and used more often in adults, where the remaining fertility to protect is smaller and cumulative malignancy exposure is longer. It is not the default in children.

Mechanism Target:

Neoplastic Transformation of Retained Mullerian Epithelium — Removing the epithelium removes the tissue at risk of malignant change.

Show evidence (1 reference)

PMID:26246705 SUPPORT Human Clinical

"Early treatment is needed to maintain fertility and to prevent the occurrence of malignancy in remnant müllerian structures."

States prevention of remnant malignancy as the goal of removing the structures, which is the mechanism this treatment targets.

Show evidence (1 reference)

PMID:35386545 SUPPORT Human Clinical

"in other reports, the Mullerian structures are excised, especially in adults"

Records excision as a used option and its skew toward adult patients.

Inguinal Hernia Repair

Category: Therapeutic Action: Herniorrhaphy NCIT:C168249

Platform: Surgery

Repair of the associated inguinal hernia, frequently the operation at which PMDS is first recognized. Recognizing Mullerian structures in the sac should stop reflexive excision and prompt karyotype, gonadal biopsy and endocrine assessment before further surgery.

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"The main surgical considerations are repairing associated inguinal hernias; preserving gonadal function and fertility and minimising the risk of malignant change by early orchidopexy and careful preservation of gonadal vasculature and vasal and ductal structures; and long-term surveillance for..."

Lists hernia repair first among the surgical considerations in PMDS.

PMID:35386545 SUPPORT Human Clinical

"Gonadal biopsy and karyotype before proceeding to orchidopexy will help to give the family time to understand the condition, to get reassurance about the karyotype, and to get objective reassurance about the presence of normal testicular tissue."

Supports pausing for karyotype and biopsy once Mullerian structures are found intraoperatively.

Long-term Surveillance of Preserved Mullerian Remnants and Pexed Testes

Category: Monitoring Action: Imaging surveillance of retained Mullerian structures Ontology label: Ultrasound Imaging NCIT:C17230

Where the remnant is left in situ, annual ultrasound with periodic MRI is used to watch for growth or a new mass, alongside examination of the pexed testes. There is no evidence base establishing either the optimal modality or the interval; the practice follows from the malignancy risk rather than from trial data, and that uncertainty should be stated to families.

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"If the Müllerian remnant is left in situ, the literature advocates regular ultrasound surveillance, such as annually, to assess for change in size or new mass lesions"

States the surveillance practice for a preserved remnant.

PMID:35386545 SUPPORT Human Clinical

"At present, there is no data to suggest whether one modality is superior for surveillance purposes, and there is no data to guide the frequency of surveillance should it be undertaken."

Records the absence of an evidence base for modality or interval, which is the caveat curated in this treatment's description.

Sperm Cryopreservation

Category: Therapeutic Action: sperm cryopreservation Ontology label: Cryopreservation NCIT:C16475

Platform: Other

Banking of any sperm recovered from the ejaculate, once semen analysis (see diagnosis) shows that sperm are present. Banking before any further Mullerian or inguinal surgery matters because the vasa run in the wall of the remnant and each operation carries its own risk of obstructing them.

Mechanism Target:

Impaired Spermatogenesis and Excurrent Duct Compromise — Banking sperm while they are still obtainable preserves reproductive options against the progressive and iatrogenic components of this mechanism, without altering the mechanism itself.

Show evidence (1 reference)

PMID:39682529 SUPPORT Human Clinical

"The mechanisms involved are cryptorchidism and late orchidopexy, male excretory duct anomalies, and iatrogenic lesions."

Names the iatrogenic and progressive components of the infertility that banking before further surgery is intended to outrun.

Show evidence (1 reference)

PMID:33532339 SUPPORT Human Clinical

"We intended to cryopreserve sperms, however, both patients were azoospermic."

Sperm banking planned at the time of surgery in adult PMDS, and the dependence of that plan on the semen-analysis result.

Testicular Sperm Extraction

Category: Therapeutic Action: microdissection testicular sperm extraction Ontology label: Sperm Retrieval NCIT:C94427

Platform: Surgery

Microdissection testicular sperm extraction (micro-TESE) in men with azoospermia, to recover spermatozoa directly from the testis when none reach the ejaculate. This is the intervention that addresses the excurrent-duct limb of the infertility, since sperm may be produced but unable to leave. Reported success is roughly one man in two, comparable to non-obstructive azoospermia without PMDS, so a negative result is common and should be anticipated in counselling.

Mechanism Target:

Impaired Spermatogenesis and Excurrent Duct Compromise — Retrieving sperm from the testis bypasses the obstructed or injured excurrent duct that this mechanism describes.

Show evidence (1 reference)

PMID:35052499 SUPPORT Human Clinical

"Micro-TESE was performed and sperms were observed; Müllerian remnants were removed laparoscopically."

Sperm recovered directly from the testis in a PMDS patient who was azoospermic on semen analysis, which is what this treatment targets.

Show evidence (1 reference)

PMID:35052499 SUPPORT Human Clinical

"No sperms in semen was observed in cases 1 and 2 of this study, and the micro-TESE success rate was 50%"

The reported retrieval rate in this series, and the comparison with non-PMDS azoospermia that sets the counselling expectation.

Intracytoplasmic Sperm Injection

Category: Therapeutic Action: intracytoplasmic sperm injection Ontology label: Intracytoplasmic Sperm Injection NCIT:C185482

Platform: Other

Assisted fertilization using surgically retrieved sperm. It is the step that converts a successful extraction into a chance of biological paternity, and it is the only route available once the excurrent ducts are congenitally abnormal or have been injured during Mullerian or inguinal surgery.

Mechanism Target:

Impaired Spermatogenesis and Excurrent Duct Compromise — Fertilization in vitro removes the requirement for sperm transit through the compromised excurrent duct entirely.

Show evidence (1 reference)

PMID:39682529 SUPPORT Human Clinical

"If spermatogenesis is present, testicular sperm extraction followed by ICSI may be used to facilitate conception in cases of congenital or iatrogenic lesions of the male excretory ducts"

Names both the indication - congenital or iatrogenic excretory duct lesions - and the extraction-plus-injection sequence this treatment completes.

Show evidence (1 reference)

PMID:32172781 SUPPORT Human Clinical

"Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."

Sets the baseline this treatment is meant to improve on: unassisted paternity depends on an intact excretory duct, which assisted fertilization does not require.

Orchidectomy for a Nonviable or Malignancy-Suspicious Testis

Category: Therapeutic Action: orchidectomy of a nonviable or malignancy-suspicious testis Ontology label: Orchiectomy NCIT:C15288

Platform: Surgery

Removal of a testis that is atrophic, unsalvageable after repeated attempts at fixation, or carries a mass suspicious for malignancy. It is the counterpart to orchidopexy and not an alternative to it: the aim throughout is to place a viable testis in the scrotum, and orchidectomy is what remains once that testis has been lost. Because the malignancy risk in PMDS is carried by the malpositioned gonad, an intra-abdominal testis that cannot be brought down and cannot be examined is the situation in which the decision arises.

Mechanism Target:

Germ Cell Neoplasia Risk in the Malpositioned Testis — Removing a testis that cannot be placed in the scrotum or examined removes the tissue that carries the germ cell tumour risk.

Show evidence (1 reference)

PMID:39682529 SUPPORT Human Clinical

"In September 2021, at the age of 12, surgery was repeated on the left hemiscrotum, and a small atrophic left testicle was discovered, for which an orchidectomy was performed, taking into account the risk of malignancy."

A worked case giving both indications together: an atrophic testis removed explicitly on the malignancy-risk rationale this link asserts.

Show evidence (1 reference)

PMID:32172781 SUPPORT Human Clinical

"Testicular malignant degeneration occurs in 33% of adults with PMDS."

The malignancy burden that makes removal of an unsalvageable, unexaminable testis a considered option rather than an abandonment of fertility.

🔬

Biochemical Markers

2

Low or undetectable serum anti-Mullerian hormone (DECREASED)

Pathograph Readouts

Readout Of AMH Ligand or AMHR2 Receptor Loss of Function Negative Diagnostic

A low or undetectable serum AMH in a phenotypically male infant with Mullerian structures points to a ligand-side (AMH) defect and directs sequencing to AMH first.

Show evidence (1 reference)

PMID:17161334 SUPPORT Human Clinical

"Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."

States the measurement and the genotype it reports on, which is the readout relationship asserted here.

Show evidence (1 reference)

PMID:8872466 SUPPORT Human Clinical

"The type of genetic defect could be predicted from the level of serum AMH which is very low or undetectable in patients with AMH mutations and at the upper limit of normal in receptor mutations."

Directly reports the low or undetectable serum AMH characteristic of ligand-gene mutations.

Normal or elevated serum anti-Mullerian hormone (NORMAL)

Pathograph Readouts

Readout Of Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme Present Absent Diagnostic

A normal or elevated serum AMH alongside retained Mullerian structures demonstrates that ligand is present and the lesion is downstream of it, at the receptor, and directs sequencing to AMHR2.

Show evidence (1 reference)

PMID:8895659 SUPPORT Model Organism

"They express both MIS mRNA and protein, showing that ligand was present, but target organs were hormone-insensitive."

The receptor-mutant mouse makes the inference explicit: measurable ligand with unresponsive target tissue localizes the lesion to the receptor.

Show evidence (3 references)

PMID:17161334 SUPPORT Human Clinical

"Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."

Reports the normal-for-age serum AMH in receptor-gene disease, the value that defines this biochemical record.

PMID:35052499 SUPPORT Human Clinical

"patients with AMH mutations usually show low or undetectable serum AMH levels compared to normal or elevated serum AMH levels found in cases with AMHR2 mutations"

States the elevated as well as normal end of the receptor-subtype range, contrasted directly against the ligand subtype.

PMID:39682529 SUPPORT Human Clinical

"Serum AMH and inhibin B were normal."

A worked case in which normal serum AMH accompanied a homozygous likely-pathogenic AMHR2 variant.

🔬

Diagnosis

8

Diagnostic Laparoscopy

Laparoscopy for impalpable or bilaterally undescended testes is the point at which most cases are recognized, because it is the only investigation that directly visualizes the retained uterus and tubes alongside the gonads. It is therefore both the commonest route to diagnosis and, when the finding is not recognized for what it is, the commonest route to a reflexive excision. Finding Mullerian and Wolffian derivatives together should stop the operation and prompt gonadal biopsy and karyotype, since other 46,XY differences of sex development can present the same way.

diagnostic laparoscopy for impalpable testes NCIT:C16969

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"Diagnostic laparoscopy for impalpable testes at age 6 months revealed bilateral intra-abdominal testes, with normal and expected testicular structure and appearance."

A worked case in which laparoscopy for impalpable testes was the investigation that established the internal anatomy.

PMID:35386545 SUPPORT Human Clinical

"With investigative laparoscopy for impalpable testes now commonplace, the recognition of FT PMDS in infancy has increased"

Attributes the rise in infant diagnosis to routine laparoscopy, which is why this is the primary diagnostic route rather than an adjunct.

Inguinoscrotal and Pelvic Ultrasound

First-line imaging for the undescended or impalpable testis, and the study that most often raises the question. Its negative predictive value for the Mullerian remnant is poor: an ultrasound that locates neither testis and reports no pelvic abnormality does not exclude PMDS, and the diagnosis is still made at laparoscopy. Ultrasound is more useful afterwards, as the routine modality for annual surveillance of a preserved remnant.

inguinoscrotal and pelvic ultrasound NCIT:C17230

Show evidence (1 reference)

PMID:35386545 SUPPORT Human Clinical

"Initial ultrasound scan of the scrotum and pelvis did not identify the testes and did not detect any pelvic abnormality."

A negative ultrasound in a patient subsequently shown at laparoscopy to have intra-abdominal testes and a Mullerian remnant, which is the limitation this record records.

Pelvic Magnetic Resonance Imaging

Cross-sectional imaging to map the retained uterus, tubes and upper vagina and to locate the testes before an operation is planned. The reported failure mode is not the scan but the request: in a series in which pelvic MRI was performed before surgery, the uterus went unreported in two of three patients, and the recommendation that follows is to tell the reporting radiologist that Mullerian remnants are suspected.

pelvic magnetic resonance imaging NCIT:C16809

Show evidence (3 references)

PMID:35052499 SUPPORT Human Clinical

"They were furtherly diagnosed with PMDS, as pelvic magnetic resonance imaging revealed the presence of Müllerian remnants."

Pelvic MRI is the study that confirmed the Mullerian remnants in all three molecularly diagnosed patients in this series.

PMID:35052499 SUPPORT Human Clinical

"In this study, two of the three patients (cases 1 and 2) underwent pelvic MRI before surgery in a local hospital, but the presence of a uterus was not reported in either of them."

Documents the reporting failure that motivates naming the suspicion on the request form, rather than treating a normal MRI report as exclusion.

PMID:35052499 SUPPORT Human Clinical

"For patients with suspected PMDS, preoperative AMH hormone examination, genetic analysis, and MRI after informing the imaging physician of possible uterine remnants can improve the diagnosis rate of PMDS."

States the combined preoperative pathway - hormone measurement, genetics and a forewarned MRI - that this diagnosis section models.

Karyotype

Chromosome analysis, expected to show 46,XY. It does not diagnose PMDS, and a normal male karyotype is compatible with several other 46,XY differences of sex development. Its role is to place the patient in the right diagnostic frame before an irreversible operation, and to give the family an answer at the point where an unexpected uterus has been found.

karyotype analysis NCIT:C16768

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"Gonadal biopsy and karyotype before proceeding to orchidopexy will help to give the family time to understand the condition, to get reassurance about the karyotype, and to get objective reassurance about the presence of normal testicular tissue."

States the sequencing rationale curated here: karyotype before the definitive operation rather than after it.

PMID:35052499 SUPPORT Human Clinical

"The patient had the normal 46, XY karyotype."

The expected result in a molecularly confirmed patient, establishing the karyotype as normal rather than diagnostic.

Serum Anti-Mullerian Hormone with Gonadotropin and Androgen Panel

Serum AMH, measured alongside inhibin B, testosterone, LH and FSH. AMH partitions the two genetic subtypes rather than establishing the diagnosis: a low or undetectable value points to the ligand gene and a normal or elevated value to the receptor gene. A normal AMH therefore does not exclude PMDS, and reading it that way is one of the routes to a missed diagnosis. Tumour markers are added when a mass is present.

serum anti-Mullerian hormone measurement NCIT:C120625

Results: Low or undetectable serum AMH in PMDS type I; normal or elevated serum AMH in PMDS type II.

The two directions are curated as separate subtype-attributed records in the biochemical section, where the discrepancy between them is the informative content.

Show evidence (2 references)

PMID:39682529 SUPPORT Human Clinical

"Serum AMH and inhibin B were normal."

A normal AMH and inhibin B in a patient subsequently shown to carry a biallelic AMHR2 variant, which is the receptor-subtype pattern.

PMID:35052499 SUPPORT Human Clinical

"He was diagnosed with azoospermia after hormone analysis"

Places the gonadotropin and androgen panel in the workup of the adult infertility presentation, which is where PMDS is often first suspected.

AMH and AMHR2 Sequencing with Copy-Number Analysis

Sequence and deletion/duplication analysis of both genes. Copy-number detection is specified rather than assumed because AMHR2 microdeletions occur, and a whole-gene deletion in trans with a point variant makes that variant look homozygous on Sanger sequencing alone - so a sequencing-only result can be both wrong about zygosity and wrong about which parent is a carrier. A wider disorder-of-sex-development panel or exome is appropriate when first-line testing is negative, and a negative result does not exclude the pathway. After a molecular diagnosis, cascade testing is offered to siblings.

AMH and AMHR2 sequencing with deletion/duplication analysis NCIT:C15709

Show evidence (4 references)

PMID:35052499 SUPPORT Human Clinical

"Three of the 11 patients had biallelic mutations in AMH or AMHR2."

The diagnostic yield of sequencing in an unselected cryptorchidism cohort, which is the basis for testing in selected cryptorchidism.

PMID:35052499 SUPPORT Human Clinical

"Copy number variants were identified using the DNA copy R package, filtered and classified by ACMG guidelines, and manually checked using the Integrative Genomics Viewer."

Records copy-number calling as part of the analysis rather than an optional add-on.

PMID:32187366 SUPPORT Human Clinical

"We report the first cases of PMDS resulting from a microdeletion of the chromosomal region 12q13.13, the locus of the gene for AMHR2."

Establishes that AMHR2 copy-number variants cause PMDS, so an assay blind to them can miss the diagnosis outright.

+ 1 more reference

Histopathological Examination of Gonadal and Mullerian Tissue

Histology of the gonadal biopsy and of any excised remnant. The biopsy confirms normal testicular tissue, which is what separates PMDS from the gonadal dysgenesis differentials; examination of the remnant confirms Mullerian epithelium and smooth muscle and is the point at which unsuspected malignancy would be found.

histopathological examination of gonadal and Mullerian tissue NCIT:C18190

Show evidence (2 references)

PMID:35386545 SUPPORT Human Clinical

"Histology of bilateral gonadal biopsy showed normal testicular tissue."

The expected gonadal result, which is the finding that excludes gonadal dysgenesis.

PMID:35052499 SUPPORT Human Clinical

"The patient was histologically confirmed to have PMDS"

Histology of the excised remnant as the confirmatory step in a molecularly diagnosed patient.

Semen Analysis

Assessment of the ejaculate in an adult, and the first step of the fertility workup. Where the excurrent ducts are intact and at least one testis is scrotal, spontaneous paternity is possible, so the result decides whether sperm can be banked from the ejaculate or must be sought by testicular extraction. Azoospermia is reported in adults presenting with infertility, and in some men the reproductive workup is the route by which the syndrome is first recognized.

semen analysis NCIT:C25294

No NCIT term is labelled "semen analysis"; an OLS search of NCIT for "semen analysis" returned nothing. NCIT:C74663 Spermatozoa Cell Count is reachable from Clinical Intervention or Procedure but names only one component of the analysis, so the parent Laboratory Procedure is bound and the specificity is carried in preferred_term.

Show evidence (2 references)

PMID:35052499 SUPPORT Human Clinical

"came to our medical center for routine semen analysis"

Semen analysis as the entry point to the reproductive workup in an adult later diagnosed with PMDS.

PMID:33532339 SUPPORT Human Clinical

"Semen analysis showed both patients were azoospermic."

The result semen analysis returned in two adult PMDS cases presenting with infertility.

📊

Prevalence

1

Worldwide

Cases In Literature Unknown

No population-based prevalence estimate exists. Case counts are the only figure reported, and they are a lower bound: PMDS is frequently found incidentally at surgery and is presumed under-ascertained.

Show evidence (1 reference)

PMID:39682529 SUPPORT Human Clinical

"At the time of writing, fewer than 300 cases have been reported in the literature."

A 2024 case report with literature review gives the cumulative reported case count, the only occurrence figure available.

🐁

Animal Models

3

Amhr2 (MIS type II receptor) mutant mouse

Receptor-null male mice retain a uterus and oviducts alongside a complete male reproductive tract, phenocopying the ligand-null mouse. They produce sperm but are largely infertile because the retained female structures obstruct sperm transfer. The model reproduces the PMDS dissociation and shows that ligand and receptor loss converge on the same phenotype.

Species

Mouse

Genotype

Amhr2 null (MIS type II receptor mutant)

Publication

PMID:8895659

Pathograph links

Failure of Mullerian Duct Regression recapitulates fidelity: high observes: organism Genetic ablation of the AMH type II receptor in the mouse reproduces retention of uterus and oviducts in an otherwise male animal.

Limitations: Mouse testes descend on a different anatomical schedule from human testes, so the model does not reproduce the cryptorchidism and inguinal presentations that dominate the human clinical picture. Infertility in the mouse arises mechanically from obstructed sperm transfer rather than from the malpositioned-testis and surgical-injury routes that operate in humans.

Show evidence (1 reference)

PMID:8895659 SUPPORT Model Organism

"MIS receptor mutant males develop as internal pseudohermaphrodites, possessing a complete male reproductive tract and also a uterus and oviducts, a phenocopy of MIS ligand-deficient male mice."

Reports the retained Mullerian derivatives alongside an intact male tract, the node this model is linked to.

Show evidence (1 reference)

PMID:8895659 SUPPORT Model Organism

"All produce sperm, but the majority were infertile because the presence of their female reproductive organs blocks sperm transfer into females."

Establishes the model's reproductive phenotype and the mechanical route by which it arises in the mouse.

Mullerian-mesenchyme-specific Bmpr1a conditional knockout mouse

Deleting the shared type I BMP receptor Bmpr1a specifically in Mullerian duct mesenchyme leaves oviducts and uteri in male mice, identifying Bmpr1a as the type I receptor for AMH-induced regression. This is the model that establishes the receptor-complex step downstream of AMHR2.

Species

Mouse

Genotype

Bmpr1a (Alk3) conditional knockout in Mullerian duct mesenchyme

Publication

PMID:12368913

Pathograph links

Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme recapitulates fidelity: moderate observes: molecular Tissue-specific deletion isolates the type I receptor requirement within the periductal mesenchyme.

Limitations: BMPR1A variants have not been reported as a cause of human PMDS, so the model establishes the pathway architecture rather than a human disease gene. Type I receptor usage is partly redundant in mouse, so a single conditional knockout may not map cleanly onto the human requirement.

Show evidence (1 reference)

PMID:12368913 SUPPORT Model Organism

"These results identify Bmpr1a as a type I receptor for Amh-induced regression of Müllerian ducts."

States the conclusion the model supports about the receptor complex annotated on this node.

Show evidence (1 reference)

PMID:12368913 SUPPORT Model Organism

"Amh induces regression by binding to a specific type II receptor (Amhr2) expressed in the mesenchyme surrounding the ductal epithelium."

Establishes that the mesenchyme this model manipulates is the AMH-receiving compartment, which is what makes the conditional knockout informative for the human receptor step.

Canine AMHR2 p.Arg81Ter Miniature Schnauzer (naturally occurring PMDS)

Naturally occurring, breed-enriched PMDS in the Miniature Schnauzer, caused by a nonsense variant in the third exon of AMHR2 that abolishes receptor expression. Affected males retain oviducts, uterus, uterine body, cervix and a cranial vagina, and about half are unilaterally or bilaterally cryptorchid. This is the point of the model: it reproduces the retained Mullerian derivatives that the mouse also reproduces, and in addition the failure of testicular descent that the mouse does not, so it is the only available whole-organism system in which the tethering step can be observed rather than inferred. It is a spontaneous, outbred, population-level model rather than an engineered one - the variant was found at an allele frequency of 0.16 among 216 North American Miniature Schnauzers, with 27 percent carriers.

Species

Dog

Genotype

AMHR2 c.241C>T (p.Arg81Ter) homozygous, sex-limited autosomal recessive

Background

Miniature Schnauzer (Canis lupus familiaris, NCBITaxon:9615)

Publication

PMID:29194807

Pathograph links

Mechanical Tethering of the Testis by Retained Mullerian Structures partially recapitulates fidelity: moderate observes: organism Affected dogs carry the retained Mullerian derivatives and, unlike the Amh-null and Amhr2-null mouse, present with cryptorchidism, so retention and failed descent co-occur in one animal as they do in human PMDS.

Limitations: Cryptorchidism is reported in roughly half of affected dogs rather than in all of them, and canine testicular descent is not on the human schedule, so the co-occurrence establishes that retention and failed descent travel together in this species without demonstrating the tether itself. The allele is breed-restricted: the same study sequenced AMH and AMHR2 in a PMDS-affected Belgian Malinois and found no causal variant, so canine PMDS is not one genetic entity. The cohort is a genotyping survey, not a gubernacular or cord-anatomy study, and no measurement of the attachment between remnant and testis was made.

Readouts

Proportion of PMDS-affected dogs that are cryptorchid

Direction: INCREASED

Interpretation: Failure of descent in about half of affected animals, against a low breed background rate, is the observation that distinguishes this model from the rodent models of the same pathway.

Show evidence (1 reference)

PMID:29194807 SUPPORT Model Organism

"An estimated 50% of male dogs affected by PMDS are cryptorchid"

Reports the measurement behind this readout.

Mullerian derivatives retained in affected males

Direction: INCREASED

Interpretation: The retained structures are present and anatomically continuous with the male tract, which is the substrate the tether requires.

Show evidence (1 reference)

PMID:29194807 SUPPORT Model Organism

"Affected males can have oviducts, a uterus, uterine body, cervix, and even a cranial vagina that enters into the prostate"

Records the retained derivatives in affected dogs, the anatomical finding this readout measures.

Show evidence (1 reference)

PMID:29194807 SUPPORT Model Organism

"An important consequence of this syndrome is bilateral or unilateral cryptorchidism, which often occurs in PMDS-affected dogs and causes infertility as well as increased risk for testicular tumors"

Establishes that in the dog the retained Mullerian structures and failed descent occur together and carry the same downstream consequences as in human PMDS, which is what makes this model informative for the tethering node.

Notes

Curated in response to the HUMAN_MODEL_MISMATCH discussion in this entry, which argues that the dog is the better model for the mechanical-tethering step and proposes canine descent phenotyping as the resolving experiment. Sertoli-cell tumours are reported in canine PMDS in the wider veterinary literature, but no exactly quotable statement of that was found in the references cached for this entry, so the tumour claim here is kept at the level the sources support - increased risk of testicular tumours.

Show evidence (4 references)

PMID:29194807 SUPPORT Model Organism

"The genetic basis for PMDS in Miniature Schnauzers is a sex-limited autosomal recessive C to T transition (c.241C>T; p.R81*) nonsense mutation in the third exon of the AMHR2 gene"

Names the causal allele and its inheritance, establishing that the canine lesion is in the same gene as human PMDS type II.

PMID:29194807 SUPPORT Model Organism

"As a result, AMHR2 is not expressed, and the Müllerian ducts fail to regress in affected males."

States the molecular consequence, matching the receptor-loss step curated at the head of this entry's pathograph.

PMID:29194807 SUPPORT Model Organism

"The Miniature Schnauzer cohort had an AMHR2 mutation allele frequency of 0.16 and a carrier genotypic frequency of 0.27."

Quantifies how common the allele is in the breed, which is what makes the model practically available rather than a single case report.

+ 1 more reference

{ }

Source YAML

click to show

name: Persistent Mullerian Duct Syndrome
creation_date: "2026-09-05T20:30:00Z"
category: Mendelian
description: >-
  Persistent Mullerian duct syndrome (PMDS) is a rare autosomal recessive 46,XY
  difference of sex development in which a uterus and Fallopian tubes persist in
  an individual who has histologically normal testes and normally virilized male
  external genitalia. Fetal Sertoli cells normally secrete anti-Mullerian hormone
  (AMH), a TGF-beta family ligand that signals through the type II receptor
  AMHR2 on the mesenchyme surrounding the Mullerian ducts and drives their
  regression during a narrow window of male sex differentiation. Biallelic
  loss-of-function variants in AMH (PMDS type I) or AMHR2 (PMDS type II) break
  that single arm of male differentiation while leaving the Leydig-cell
  testosterone arm intact, so Wolffian derivatives develop and external
  virilization proceeds normally. The retained Mullerian structures tether the
  testes and prevent normal descent, so most individuals present with
  cryptorchidism, inguinal hernia, or transverse testicular ectopia, and the
  diagnosis is usually made incidentally at hernia repair or orchidopexy. PMDS is
  emphatically not a gonadal dysgenesis: the gonads are testes and produce
  testosterone normally.
disease_term:
  preferred_term: persistent Mullerian duct syndrome
  term:
    id: MONDO:0009857
    label: persistent Mullerian duct syndrome
synonyms:
- Persistent Muellerian duct syndrome
- Persistent Mullerian derivatives
- Hernia uteri inguinale
- Female genital ducts in otherwise normal male
- PMDS
parents:
- 46,XY disorder of sex development
- Disorder of sex development
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0009857
      label: persistent Mullerian duct syndrome
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
    mapping_justification: Primary MONDO identifier for the disease.
inheritance:
- name: Autosomal recessive
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Affected individuals carry biallelic (homozygous or compound heterozygous)
    loss-of-function variants in AMH or AMHR2. Heterozygous carriers are
    unaffected.
  evidence:
  - reference: PMID:8872466
    reference_title: "A 27 base-pair deletion of the anti-müllerian type II receptor gene is the most common cause of the persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All AMH and AMH receptor mutations were consistent with an autosomal recessive mode of transmission."
    explanation: >-
      A 38-family molecular series states the inheritance mode directly for both
      the ligand and the receptor gene.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Persistent Müllerian duct syndrome (PMDS) is a rare autosomal recessive disorder of sexual development in males, defined by the presence of Müllerian remnants with otherwise normal sexual differentiation."
    explanation: >-
      An exome-sequencing case series restates autosomal recessive inheritance
      alongside the defining internal/external discordance.
prevalence:
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: UNKNOWN
  notes: >-
    No population-based prevalence estimate exists. Case counts are the only
    figure reported, and they are a lower bound: PMDS is frequently found
    incidentally at surgery and is presumed under-ascertained.
  evidence:
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "At the time of writing, fewer than 300 cases have been reported in the literature."
    explanation: >-
      A 2024 case report with literature review gives the cumulative reported
      case count, the only occurrence figure available.
has_subtypes:
- name: PMDS type I
  display_name: PMDS type I (AMH ligand deficiency)
  subtype_term:
    preferred_term: Persistent Mullerian Duct Syndrome Type I
    term:
      id: NCIT:C120189
      label: Persistent Mullerian Duct Syndrome Type I
  description: >-
    PMDS caused by biallelic loss-of-function variants in AMH, the gene encoding
    the anti-Mullerian hormone ligand. Because the ligand itself is absent or
    non-functional, serum AMH is low or undetectable, which distinguishes type I
    from type II biochemically. The clinical picture is otherwise
    indistinguishable from type II.
  genes:
  - preferred_term: AMH
    term:
      id: hgnc:464
      label: AMH
  evidence:
  - reference: PMID:8872466
    reference_title: "A 27 base-pair deletion of the anti-müllerian type II receptor gene is the most common cause of the persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The type of genetic defect could be predicted from the level of serum AMH which is very low or undetectable in patients with AMH mutations and at the upper limit of normal in receptor mutations."
    explanation: >-
      Establishes the ligand-versus-receptor split and the serum AMH measurement
      that separates the two subtypes.
- name: PMDS type II
  display_name: PMDS type II (AMHR2 receptor defect)
  subtype_term:
    preferred_term: Persistent Mullerian Duct Syndrome Type II
    term:
      id: NCIT:C120190
      label: Persistent Mullerian Duct Syndrome Type II
  description: >-
    PMDS caused by biallelic loss-of-function variants in AMHR2, the gene
    encoding the AMH type II receptor. The ligand is made normally but the
    target tissue cannot respond, so serum AMH is normal or elevated for age. A
    27-bp deletion in the kinase domain is the single most common allele,
    concentrated in individuals of northern European ancestry.
  genes:
  - preferred_term: AMHR2
    term:
      id: hgnc:465
      label: AMHR2
  evidence:
  - reference: PMID:17161334
    reference_title: "Anti-Müllerian hormone receptor defect."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."
    explanation: >-
      States the receptor-subtype serum AMH pattern that defines type II against
      type I. ("AMH type II mutations" here means AMH receptor type II
      mutations.)
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most common mutation, a 27-bp deletion in the kinase domain, was found in 30 patients of mostly Northern European origin."
    explanation: >-
      Documents the recurrent AMHR2 kinase-domain deletion and its ancestry
      distribution.
pathophysiology:
- name: AMH Ligand or AMHR2 Receptor Loss of Function
  biological_scale: MOLECULAR
  description: >-
    Biallelic loss-of-function variants abolish either the anti-Mullerian
    hormone ligand secreted by fetal Sertoli cells (type I) or the type II
    serine/threonine kinase receptor AMHR2 that receives it (type II). About
    12 percent of clinically diagnosed cases carry no identified variant in
    either gene, implying at least one further pathway component.
  genes:
  - preferred_term: AMH
    term:
      id: hgnc:464
      label: AMH
  - preferred_term: AMHR2
    term:
      id: hgnc:465
      label: AMHR2
  cell_types:
  - preferred_term: fetal Sertoli cell
    term:
      id: CL:0000216
      label: Sertoli cell
  molecular_functions:
  - preferred_term: anti-Mullerian hormone receptor activity
    modifier: LOSS_OF_FUNCTION
    term:
      id: GO:1990272
      label: anti-Mullerian hormone receptor activity
  downstream:
  - target: Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme
    causal_link_type: DIRECT
    description: >-
      Absent ligand or a non-functional receptor removes the input to the
      AMH signaling cascade in the target mesenchyme.
    evidence:
    - reference: PMID:32172781
      reference_title: "Persistent Müllerian duct syndrome: an update."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Mutations inactivating AMH or AMH receptor type 2 (AMHR2) are responsible for persistent Müllerian duct syndrome (PMDS) in otherwise normally virilised 46,XY males."
      explanation: >-
        Attributes the syndrome to inactivation of either the ligand or its
        type II receptor, which is the step this edge asserts.
  evidence:
  - reference: PMID:31301298
    reference_title: "AMH and AMHR2 mutations: A spectrum of reproductive phenotypes across vertebrate species."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AMH is expressed in Sertoli cells of the fetal and adult testes and granulosa cells of the postnatal ovary."
    explanation: >-
      Locates AMH production in fetal Sertoli cells, the cell type annotated on
      this node.
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In 12% of cases, no mutation of AMH or AMHR2 has been detected, suggesting a disruption of other pathways involved in Müllerian regression."
    explanation: >-
      Supports the statement that a minority of cases have variants in neither
      gene.
- name: Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme
  biological_scale: MOLECULAR
  description: >-
    AMHR2 is expressed on the mesenchyme surrounding the Mullerian duct
    epithelium. Ligand binding to AMHR2 recruits a shared type I BMP receptor
    (BMPR1A/ALK3, with ACVR1 also implicated) and activates receptor-regulated
    SMADs. Loss of ligand or receptor collapses the whole cascade at its first
    step, so the downstream SMAD-dependent transcriptional program that
    dismantles the duct is never run.
  cell_types:
  - preferred_term: Mullerian duct mesenchymal cell
    term:
      id: CL:0008019
      label: mesenchymal cell
  biological_processes:
  - preferred_term: anti-Mullerian hormone receptor signaling pathway
    modifier: LOSS_OF_FUNCTION
    term:
      id: GO:1990262
      label: anti-Mullerian hormone receptor signaling pathway
  - preferred_term: SMAD protein signal transduction
    modifier: DECREASED
    term:
      id: GO:0060395
      label: SMAD protein signal transduction
  downstream:
  - target: Failure of Mullerian Duct Regression
    causal_link_type: DIRECT
    description: >-
      Without receptor-complex activation and SMAD signaling in the periductal
      mesenchyme, the duct is not induced to regress.
    evidence:
    - reference: PMID:12368913
      reference_title: "Requirement of Bmpr1a for Müllerian duct regression during male sexual development."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Here we show that targeted disruption of the widely expressed type I bone morphogenetic protein (BMP) receptor Bmpr1a (also known as Alk3) in the mesenchymal cells of the Müllerian ducts leads to retention of oviducts and uteri in males."
      explanation: >-
        A conditional mouse knockout shows that breaking the receptor complex
        specifically in Mullerian duct mesenchyme is sufficient to leave the
        ducts in place, which is the causal step this edge asserts.
  evidence:
  - reference: PMID:31301298
    reference_title: "AMH and AMHR2 mutations: A spectrum of reproductive phenotypes across vertebrate species."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AMHR2 is expressed in mesenchyme adjacent to the Müllerian ducts, and in Sertoli, Leydig, and granulosa cells."
    explanation: >-
      Places the receptor on the periductal mesenchyme, the cell type annotated
      on this node.
  - reference: PMID:17161334
    reference_title: "Anti-Müllerian hormone receptor defect."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Like other members of the transforming growth factor beta (TGF-beta) family, AMH signals through two serine/threonine kinase receptors, of which type II is specific, and type I is shared with the bone morphogenetic protein family."
    explanation: >-
      Supports the two-receptor architecture, with a ligand-specific type II
      receptor recruiting a shared type I receptor.
  - reference: PMID:18391537
    reference_title: "The Müllerian duct: recent insights into its development and regression."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Besides AMH and its specific type II receptor AMHR2 two different type I receptors as well as different SMAD family members have been shown to be involved in the AMH signaling cascade."
    explanation: >-
      Supports SMAD family involvement downstream of AMHR2, the second process
      annotated on this node.
- name: Failure of Mullerian Duct Regression
  biological_scale: TISSUE
  description: >-
    Mullerian duct regression is a developmentally scheduled event confined to a
    narrow window of male fetal differentiation; AMH signaling is required
    during that window and cannot act later. When the signal fails, the ducts
    are not dismantled and differentiate along their default path into uterus,
    Fallopian tubes, and upper vagina.
  biological_processes:
  - preferred_term: Mullerian duct regression
    modifier: ABSENT
    term:
      id: GO:0001880
      label: Mullerian duct regression
  locations:
  - preferred_term: Mullerian duct
    term:
      id: UBERON:0003890
      label: Mullerian duct
  downstream:
  - target: Presence of Uterus in 46,XY Individual
    causal_link_type: DIRECT
    description: >-
      The unregressed ducts differentiate into uterus, Fallopian tubes and upper
      vagina.
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Müllerian structures completely vanish as a result of the effects of AMH during the tenth week of fetal development, which mediates normal sexual differentiation in males"
      explanation: >-
        Dates the normal AMH-driven disappearance of the Mullerian structures to
        a narrow fetal window, so failure of that signal leaves them in place.
  - target: Mechanical Tethering of the Testis by Retained Mullerian Structures
    causal_link_type: DIRECT
    description: >-
      The persisting duct derivatives are physically continuous with the
      testis and its cord structures.
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The Müllerian duct is attached to the testicles and prevents them from descending to the scrotum from the inguinal rings."
      explanation: >-
        States the anatomical attachment between the retained duct and the
        testis that produces the tether.
  - target: Neoplastic Transformation of Retained Mullerian Epithelium
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Retained Mullerian epithelium persists lifelong and is at risk of
      malignant change, though far less often than the malpositioned testes.
    evidence:
    - reference: PMID:12218580
      reference_title: "A case of clear cell adenocarcinoma of the müllerian duct in persistent müllerian duct syndrome: the first reported case."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This represents the first reported case of malignant change of the persistent Müllerian duct structures in persistent Müllerian duct syndrome."
      explanation: >-
        Documents that the retained Mullerian tissue itself can undergo
        malignant transformation, which is the claim of this edge.
  evidence:
  - reference: PMID:17161334
    reference_title: "Anti-Müllerian hormone receptor defect."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Anti-Müllerian hormone (AMH), produced by gonadal somatic cells, is mainly responsible for the regression of Müllerian ducts--the anlagen of uterus and Fallopian tubes--during male sex differentiation."
    explanation: >-
      Identifies Mullerian duct regression as the AMH-dependent process, and the
      uterus and Fallopian tubes as the structures at stake.
- name: Preserved Leydig Cell Androgen Production and Signaling
  biological_scale: MOLECULAR
  description: >-
    AMH and testosterone are two independent arms of male differentiation with
    different sources and different targets. PMDS breaks only the AMH arm.
    Leydig cells, testosterone biosynthesis, and androgen receptor signaling are
    all intact, which is why this is a dissociation and not a global failure of
    masculinization.
  cell_types:
  - preferred_term: Leydig cell
    term:
      id: CL:0000178
      label: Leydig cell
  biological_processes:
  - preferred_term: testosterone biosynthetic process
    term:
      id: GO:0061370
      label: testosterone biosynthetic process
  - preferred_term: androgen receptor signaling pathway
    term:
      id: GO:0030521
      label: androgen receptor signaling pathway
  downstream:
  - target: Normal Wolffian Duct Development and Male External Virilization
    causal_link_type: DIRECT
    description: >-
      Intact fetal testosterone maintains the Wolffian ducts and drives external
      genital masculinization.
    evidence:
    - reference: PMID:35386545
      reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The defect results in the coexistence of both Wolffian and Müllerian duct structures in a phenotypic male, as external virilisation is complete due to the presence of testosterone."
      explanation: >-
        Attributes the complete external virilization specifically to preserved
        testosterone, which is the causal step this edge asserts.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Male sex differentiation is driven by two hormones, testosterone and anti-Müllerian hormone (AMH), responsible for regression of Müllerian ducts in male fetuses."
    explanation: >-
      Establishes the two-hormone architecture in which only the AMH arm is
      broken in PMDS.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In addition, the presence of Leydig cells results in the secretion of testosterone, which directs localised differentiation of Wolffian duct structures including the epididymis, vas deferens, seminal vesicles, and ejaculatory ducts."
    explanation: >-
      Names Leydig-cell testosterone as the driver of Wolffian development, the
      preserved arm annotated on this node.
- name: Normal Wolffian Duct Development and Male External Virilization
  biological_scale: ORGANISM
  description: >-
    Epididymis, vas deferens, seminal vesicles and ejaculatory ducts form
    normally, the external genitalia are unambiguously male, and pubertal
    virilization proceeds. This is the feature that distinguishes PMDS from
    gonadal dysgenesis and from androgen-pathway disorders of sex development,
    in which external masculinization is incomplete.
  biological_processes:
  - preferred_term: male genitalia development
    term:
      id: GO:0030539
      label: male genitalia development
  - preferred_term: mesonephric duct development
    term:
      id: GO:0072177
      label: mesonephric duct development
  downstream:
  - target: Delayed and Incidental Diagnosis
    causal_link_type: DIRECT
    description: >-
      Because nothing about the external phenotype is atypical, there is no
      prompt to look for internal Mullerian structures.
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "PMDS in cryptorchidism patients are easily ignored as most previous cases were diagnosed incidentally when Müllerian remnants were detected during ultrasonographic evaluation of undescended testes or inguinal hernia."
      explanation: >-
        Links the absence of an external cue to incidental, delayed recognition,
        which is the step this edge asserts.
  evidence:
  - reference: PMID:31301298
    reference_title: "AMH and AMHR2 mutations: A spectrum of reproductive phenotypes across vertebrate species."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AMH or AMHR2 mutations in mammals lead to the development of Persistent Müllerian Duct Syndrome (PMDS), a recessive condition in which affected males are fully virilized but retain Müllerian duct-derived tissues, including a uterus and oviducts, and in human and dog, undescended testes."
    explanation: >-
      States the dissociation directly: full virilization alongside retained
      Mullerian derivatives.
  - reference: PMID:27329391
    reference_title: "Persistent mullerian duct syndrome: A 24-year experience."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients were genotypically male."
    explanation: >-
      Confirms the 46,XY genotype across a 27-patient surgical series, so the
      retained structures are not a chromosomal sex discordance.
- name: Mechanical Tethering of the Testis by Retained Mullerian Structures
  biological_scale: TISSUE
  description: >-
    The retained uterus and Fallopian tubes are anatomically continuous with the
    testis and its cord, and the vasa deferentia run in the wall of the retained
    structures. This attachment physically restrains testicular descent, which is
    why cryptorchidism, hernia uteri inguinale and transverse testicular ectopia
    are the presenting findings rather than incidental co-occurrences.
  locations:
  - preferred_term: Mullerian duct
    term:
      id: UBERON:0003890
      label: Mullerian duct
  downstream:
  - target: Cryptorchidism
    causal_link_type: DIRECT
    description: >-
      The tethered testis cannot complete its descent into the scrotum.
    evidence:
    - reference: PMID:33532339
      reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "It is likely that the mechanical effect of the persistent Mullerian duct structure produces cryptorchidism by preventing normal testicular descent."
      explanation: >-
        States the mechanical causal claim from retained structure to
        cryptorchidism, which is exactly this edge.
  - target: Ectopic Testis
    causal_link_type: DIRECT
    description: >-
      The same tether can carry a testis across the midline into the
      contralateral inguinal canal or hemiscrotum.
    evidence:
    - reference: PMID:33532339
      reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This mechanical effect may also lead to the transvers ectopia of testis across the midline."
      explanation: >-
        Extends the same mechanical mechanism to transverse testicular ectopia.
        (The source's spelling of "transvers" is reproduced verbatim.)
  - target: Inguinal Hernia
    causal_link_type: DIRECT
    description: >-
      Mullerian structures and the tethered testis herniate through the inguinal
      canal, the classic hernia uteri inguinale presentation.
    evidence:
    - reference: PMID:35386545
      reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "HUI usually presents with an ipsilateral hernia with ipsilateral descended testis and Müllerian structures within the hernia."
      explanation: >-
        Describes the Mullerian structures occupying the hernia sac, linking the
        retained tissue to the hernia presentation.
  - target: Germ Cell Neoplasia Risk in the Malpositioned Testis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Chronic intra-abdominal or ectopic testicular position is the intermediate
      that raises germ cell tumour risk.
    evidence:
    - reference: PMID:9187705
      reference_title: "Surgical management of persistent müllerian duct syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The risk of testicular neoplasia in persistent müllerian duct syndrome approximates the risk of neoplasia in other intra-abdominal gonads."
      explanation: >-
        Equates the PMDS tumour risk with that of intra-abdominal gonads
        generally, supporting malposition as the operative intermediate.
  - target: Impaired Spermatogenesis and Excurrent Duct Compromise
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Malposition, distortion of the excurrent ducts, and surgical injury during
      repair together degrade spermatogenesis and sperm transport.
    evidence:
    - reference: PMID:32172781
      reference_title: "Persistent Müllerian duct syndrome: an update."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."
      explanation: >-
        Makes fertility conditional on scrotal position and intact excurrent
        ducts, the two things this edge says the tether compromises.
  evidence:
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Müllerian duct is attached to the testicles and prevents them from descending to the scrotum from the inguinal rings."
    explanation: >-
      States the attachment and its mechanical consequence, which is the claim
      of this node.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Vasa deferentia were clearly identified in close association with the fallopian-tube like structures"
    explanation: >-
      Records the operative finding that the vasa run in intimate association
      with the retained Mullerian structures.
- name: Germ Cell Neoplasia Risk in the Malpositioned Testis
  biological_scale: TISSUE
  description: >-
    Undescended and ectopic testes in PMDS carry the elevated germ cell tumour
    risk of cryptorchid gonads generally. Reported rates vary widely with
    ascertainment, from roughly 5-18 percent in surgical series to 33 percent
    among adults in a large referral review; seminoma is the commonest histology.
    Early orchidopexy is the intervention that addresses it.
  downstream:
  - target: Testicular Neoplasm
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:32172781
      reference_title: "Persistent Müllerian duct syndrome: an update."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Testicular malignant degeneration occurs in 33% of adults with PMDS."
      explanation: >-
        Quantifies the realized malignancy outcome in adults, the phenotype this
        edge points at.
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The reported incidence of malignant change in the testes in PMDS generally ranges from 5 to 18%, a rate which is similar to abdominal undescended testes in men without PMDS."
    explanation: >-
      Gives the lower published range and, importantly, attributes the risk to
      testicular malposition rather than to PMDS-specific biology.
- name: Neoplastic Transformation of Retained Mullerian Epithelium
  biological_scale: TISSUE
  description: >-
    The retained uterus and Fallopian tubes remain in situ for life if not
    excised, and their epithelium can undergo malignant transformation.
    Adenocarcinoma (including clear-cell and endocervical-type) and adenosarcoma
    have been reported. This is substantially rarer than testicular malignancy
    and is the argument for either excision or lifelong imaging surveillance of
    a preserved remnant.
  downstream:
  - target: Uterine Neoplasm
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:16009404
      reference_title: "Adenocarcinoma of persistent müllerian duct remnants: case report and differential diagnosis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "We report the case of a 39-year-old man with this syndrome in association with adenocarcinoma from the retained müllerian remnants of probable endocervical origin."
      explanation: >-
        A realized carcinoma arising in the retained remnant, which is the
        outcome this edge points at.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cancer of Müllerian derivatives is less frequent."
    explanation: >-
      Supports the claim that Mullerian remnant malignancy occurs but is rarer
      than testicular malignancy.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The rate of Müllerian malignancy in the literature ranges from 3.1% to 8.4%"
    explanation: >-
      Gives the reported rate range for malignancy arising in the retained
      Mullerian structures.
- name: Impaired Spermatogenesis and Excurrent Duct Compromise
  biological_scale: TISSUE
  description: >-
    Fertility is impaired through several converging routes: prolonged
    cryptorchidism damages the germinal epithelium, the excurrent ducts are
    distorted or detached from the testis, and excision of Mullerian remnants can
    injure the vasa deferentia and their blood supply. Because the last of these
    is iatrogenic, the surgical strategy chosen has a direct bearing on
    reproductive outcome.
  downstream:
  - target: Azoospermia
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "All three patients were admitted due to azoospermia- and oligospermia-caused infertility."
      explanation: >-
        Three genetically confirmed adults presented with azoospermia or
        oligospermia, the semen outcome this edge points at.
  - target: Male Infertility
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:32172781
      reference_title: "Persistent Müllerian duct syndrome: an update."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."
      explanation: >-
        States that fertility is the exception and names the two anatomical
        conditions on which it depends.
  evidence:
  - reference: PMID:9187705
    reference_title: "Surgical management of persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Surgical excision of the infantile uterus and fallopian tubes risks damage to vasa deferentia and the deferential blood supply to the testis."
    explanation: >-
      Identifies the iatrogenic route to excurrent duct compromise named in this
      node.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It is not clear what contributes, and to what degree, to the reported fertility impairment—it may be due to uncorrected cryptorchidism, or due to coexisting congenital gonadal and Wolffian duct anomalies, or due to ischemic and structural damage to the vas and testis secondary to excision of Müllerian remnants."
    explanation: >-
      Enumerates the same converging routes and records that their relative
      contributions are not established.
- name: Delayed and Incidental Diagnosis
  biological_scale: ORGANISM
  description: >-
    Because external anatomy is normal, PMDS is usually discovered when a
    surgeon opens the inguinal canal or abdomen for something else: hernia
    repair, orchidopexy, or laparoscopy for impalpable testes. The consequence
    is repeated operations before the condition is recognized, and adult
    presentations with infertility or a tumour.
  evidence:
  - reference: PMID:27329391
    reference_title: "Persistent mullerian duct syndrome: A 24-year experience."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In 21 patients, the diagnosis was made incidentally while operating for UDT and inguinal hernia."
    explanation: >-
      Quantifies incidental intraoperative diagnosis in 21 of 27 patients in a
      24-year multicentre series.
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A high degree of suspicion and awareness is needed to diagnose this condition in order to avoid iterative surgery."
    explanation: >-
      Records the clinical cost of delayed recognition, namely repeated
      operations.
phenotypes:
- category: Genitourinary
  name: Presence of Uterus in 46,XY Individual
  frequency: OBLIGATE
  description: >-
    A uterus, Fallopian tubes and upper vagina are present in a 46,XY
    individual. This is the defining finding and is usually discovered at
    laparoscopy or laparotomy. On imaging or at operation the structures are
    small and infantile rather than functional.
  phenotype_term:
    preferred_term: Presence of uterus and Fallopian tubes in a 46,XY individual
    term:
      id: HP:0034546
      label: Presence of uterus in 46,XY individual
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A Müllerian structure resembling a uterus with bilateral fallopian tube-like structures was seen in the pelvis, along with bilateral intra-abdominal testes."
    explanation: >-
      Direct operative observation of the retained uterus and tubes alongside
      normal testes.
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "characterized by the persistence of Müllerian derivatives, the uterus and/or fallopian tubes, in otherwise normally virilized boys"
    explanation: >-
      States that uterus and/or Fallopian tubes are the persisting derivatives
      defining the condition.
- category: Genitourinary
  name: Normal Male External Genitalia
  frequency: OBLIGATE
  description: >-
    External genitalia are unambiguously male, with a normally formed penis and
    a normally sited urethral meatus, and pubertal virilization is normal. This
    is not an incidental normal finding but the diagnostic core of the syndrome:
    it is what separates PMDS from gonadal dysgenesis and from androgen-pathway
    disorders of sex development, and it is why no phenotype prompts
    investigation in infancy. No HPO term is bound because HPO codes abnormal
    findings and this phenotype is defined by the absence of one.
  phenotype_term:
    preferred_term: Normally virilized male external genitalia
  evidence:
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "On clinical examination, the external genital organs had a male phenotype, with a stretched penile length within age-appropriate limits and a normally located external urethral meatus."
    explanation: >-
      Records the examination finding of normal male external genitalia in a
      genetically confirmed AMHR2 case.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "On examination, he was noted to have a normal penis with complete prepuce and glanular urethral meatus."
    explanation: >-
      A second independent case records the same normal external examination.
- category: Genitourinary
  name: Cryptorchidism
  frequency: VERY_FREQUENT
  description: >-
    Undescended testes, unilateral or bilateral, are the usual presenting
    finding. The testes may be intra-abdominal in an ovarian position, in the
    inguinal canal, or within a hernia sac. Gonadal biopsy shows testicular
    tissue, not dysgenetic or streak gonad.
  phenotype_term:
    preferred_term: Cryptorchidism
    term:
      id: HP:0000028
      label: Cryptorchidism
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PMDS can present in one of three ways: bilateral cryptorchidism, unilateral cryptorchidism with contralateral hernia and transverse testicular ectopia."
    explanation: >-
      Names cryptorchidism, in two of its three configurations, as the
      presenting picture in a review of 157 personal plus published cases.
  - reference: PMID:27329391
    reference_title: "Persistent mullerian duct syndrome: A 24-year experience."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Ten patients presented with isolated bilateral UDT, six patients with bilateral UDT and unilateral inguinal hernia (4 left and 2 right sided inguinal hernia), and eight patients presented with right inguinal hernia and left sided UDT."
    explanation: >-
      Documents undescended testes in 24 of 27 patients in a multicentre
      surgical series.
- category: Genitourinary
  name: Inguinal Hernia
  frequency: FREQUENT
  description: >-
    Inguinal hernia, classically containing the uterus and a tube (hernia uteri
    inguinale), with the contralateral testis undescended. Repair of the hernia
    is one of the two operations at which PMDS is most often discovered.
  phenotype_term:
    preferred_term: Inguinal hernia containing Mullerian structures (hernia uteri inguinale)
    term:
      id: HP:0000023
      label: Inguinal hernia
  evidence:
  - reference: PMID:26246705
    reference_title: "Persistent Müllerian Duct Syndrome (PMDS): a Rare Anomaly the General Surgeon Must Know About."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We encountered on the same day in the operation theatre two phenotypic males aged 40 years and 10 months who had inguinal hernia on one side along with contralateral undescended testis."
    explanation: >-
      Two cases with the classic ipsilateral hernia plus contralateral
      undescended testis configuration.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "HUI usually presents with an ipsilateral hernia with ipsilateral descended testis and Müllerian structures within the hernia."
    explanation: >-
      Describes the hernia uteri inguinale variant and the Mullerian content of
      the sac.
- category: Genitourinary
  name: Ectopic Testis
  frequency: OCCASIONAL
  description: >-
    Transverse testicular ectopia, in which both testes reach the same inguinal
    canal or hemiscrotum while the contralateral side is empty. It is the rarest
    of the three anatomical presentations of PMDS and, conversely, roughly 30
    percent of transverse testicular ectopia cases carry persistent Mullerian
    structures.
  phenotype_term:
    preferred_term: Transverse testicular ectopia
    term:
      id: HP:6000460
      label: Ectopic testis
  evidence:
  - reference: PMID:33532339
    reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Transverse testicular ectopia (TTE) associated with persistent Mullerian duct syndrome (PMDS) is a rare form of male pseudohermaphroditism usually unexpectedly found at surgery for cryptorchidism or inguinal hernia in children."
    explanation: >-
      Establishes transverse testicular ectopia as a recognized PMDS
      presentation, typically found intraoperatively.
  - reference: PMID:27329391
    reference_title: "Persistent mullerian duct syndrome: A 24-year experience."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In 6 patients (male type), the PMDS was associated with transverse testicular ectopia."
    explanation: >-
      Gives the frequency of transverse testicular ectopia in a 27-patient
      series, supporting an occasional rather than typical finding.
- category: Reproductive
  name: Male Infertility
  frequency: FREQUENT
  description: >-
    Fertility is the exception rather than the rule, and depends on at least one
    testis being scrotal with intact excurrent ducts. Paternity has nonetheless
    been reported, so infertility should not be assumed.
  phenotype_term:
    preferred_term: Male infertility
    term:
      id: HP:0003251
      label: Male infertility
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."
    explanation: >-
      States that fertility is rare and conditional, supporting infertility as a
      frequent but not obligate feature.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "there are reports of fertility and paternity in men with PMDS, including in FT PMDS"
    explanation: >-
      Records documented exceptions to the general fertility impairment, which
      is why infertility is not curated as obligate.
- category: Reproductive
  name: Azoospermia
  frequency: OCCASIONAL
  description: >-
    Adults presenting through an infertility pathway are frequently azoospermic,
    with testicular biopsy showing seminiferous tubules devoid of germ cells.
  phenotype_term:
    preferred_term: Azoospermia
    term:
      id: HP:0000027
      label: Azoospermia
  evidence:
  - reference: PMID:33532339
    reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Semen analysis showed both patients were azoospermic."
    explanation: >-
      Semen analysis in two adult PMDS cases presenting with infertility.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All three patients were admitted due to azoospermia- and oligospermia-caused infertility."
    explanation: >-
      Three molecularly confirmed adults ascertained through azoospermia or
      oligospermia.
- category: Neoplastic
  name: Testicular Neoplasm
  frequency: OCCASIONAL
  description: >-
    Germ cell tumours arising in the malpositioned testes, seminoma most
    commonly. Reported frequencies range from about 5-18 percent in surgical
    series to 33 percent among adults in a large referral review; the spread
    reflects ascertainment, since adults reaching a referral centre are enriched
    for the outcome.
  phenotype_term:
    preferred_term: Testicular germ cell neoplasm
    term:
      id: HP:0010788
      label: Testicular neoplasm
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Testicular malignant degeneration occurs in 33% of adults with PMDS."
    explanation: >-
      The upper reported figure, from a review covering 157 personal cases.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Seminomas are most commonly recorded, but other Germ cell neoplasia in situ- (GCNIS-) derived testicular tumours are also reported"
    explanation: >-
      Identifies seminoma as the predominant histology, supporting the germ cell
      characterization.
- category: Neoplastic
  name: Uterine Neoplasm
  frequency: VERY_RARE
  description: >-
    Malignancy arising in the retained Mullerian remnant itself: clear cell
    adenocarcinoma, endocervical-type adenocarcinoma, and adenosarcoma have all
    been reported. Rarer than testicular malignancy, and the main reason a
    preserved remnant needs long-term imaging surveillance.
  phenotype_term:
    preferred_term: Adenocarcinoma of the retained Mullerian remnant
    term:
      id: HP:0010784
      label: Uterine neoplasm
  evidence:
  - reference: PMID:12218580
    reference_title: "A case of clear cell adenocarcinoma of the müllerian duct in persistent müllerian duct syndrome: the first reported case."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report a case of a 67-year-old man with clear cell adenocarcinoma of the remnant uterus in persistent Müllerian duct syndrome."
    explanation: >-
      A clear cell adenocarcinoma arising in the retained uterus.
  - reference: PMID:16009404
    reference_title: "Adenocarcinoma of persistent müllerian duct remnants: case report and differential diagnosis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report the case of a 39-year-old man with this syndrome in association with adenocarcinoma from the retained müllerian remnants of probable endocervical origin."
    explanation: >-
      A second, histologically different malignancy in the retained remnant.
- category: Genitourinary
  name: Testicular Atrophy
  description: >-
    Loss of testicular volume in the malpositioned gonad. The ectopic testis sits
    outside the scrotum for as long as it remains undescended, and repeated
    attempts at fixation add ischaemic insult to that exposure, so a testis that
    is viable at first presentation can be atrophic by the time of a later
    operation. This is the finding that converts the management decision from
    orchidopexy to orchidectomy, and it is the mechanism by which delayed
    diagnosis translates into permanent loss of gonadal tissue.
  phenotype_term:
    preferred_term: Testicular atrophy
    term:
      id: HP:0008734
      label: Decreased testicular size
  evidence:
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In September 2021, at the age of 12, surgery was repeated on the left hemiscrotum, and a small atrophic left testicle was discovered, for which an orchidectomy was performed, taking into account the risk of malignancy."
    explanation: >-
      An atrophic testis found at a repeat operation in a PMDS patient, and the
      consequence it carried.
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pelvic MRI revealed an intrabdominal, hypoplastic right testis and another structure, situated in the left paramedian retrovesical area, resembling an atrophic testis."
    explanation: >-
      Hypoplasia and atrophy of the malpositioned testes documented on imaging
      in the same patient at first presentation.
  notes: >-
    No frequency is recorded. The cached sources document the finding in
    individual patients but none reports a proportion, and a frequency band is a
    separate quantitative claim that would need its own evidence.
biochemical:
- name: Low or undetectable serum anti-Mullerian hormone
  subtype: PMDS type I
  presence: DECREASED
  biomarker_term:
    preferred_term: serum anti-Mullerian hormone
    term:
      id: NCIT:C101737
      label: Muellerian-Inhibiting Factor
  notes: >-
    In PMDS type I the ligand itself is absent or non-functional, so serum AMH is
    low or undetectable for age. Measured against an age-specific reference
    interval, since AMH in males is high in infancy and falls at puberty.
  evidence:
  - reference: PMID:8872466
    reference_title: "A 27 base-pair deletion of the anti-müllerian type II receptor gene is the most common cause of the persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The type of genetic defect could be predicted from the level of serum AMH which is very low or undetectable in patients with AMH mutations and at the upper limit of normal in receptor mutations."
    explanation: >-
      Directly reports the low or undetectable serum AMH characteristic of
      ligand-gene mutations.
  readouts:
  - target: AMH Ligand or AMHR2 Receptor Loss of Function
    relationship: READOUT_OF
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      A low or undetectable serum AMH in a phenotypically male infant with
      Mullerian structures points to a ligand-side (AMH) defect and directs
      sequencing to AMH first.
    evidence:
    - reference: PMID:17161334
      reference_title: "Anti-Müllerian hormone receptor defect."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."
      explanation: >-
        States the measurement and the genotype it reports on, which is the
        readout relationship asserted here.
- name: Normal or elevated serum anti-Mullerian hormone
  subtype: PMDS type II
  presence: NORMAL
  biomarker_term:
    preferred_term: serum anti-Mullerian hormone
    term:
      id: NCIT:C101737
      label: Muellerian-Inhibiting Factor
  notes: >-
    In PMDS type II the Sertoli cells make AMH normally but the target
    mesenchyme cannot respond, so serum AMH is normal for age or at the upper
    limit of normal. A normal AMH therefore does not exclude PMDS - it
    reclassifies it. This discrepancy between the two subtypes is the
    biochemical signature that separates them before sequencing.
  evidence:
  - reference: PMID:17161334
    reference_title: "Anti-Müllerian hormone receptor defect."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum AMH is normal for age in patients with AMH type II mutations and low or undetectable in those with AMH mutations."
    explanation: >-
      Reports the normal-for-age serum AMH in receptor-gene disease, the value
      that defines this biochemical record.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "patients with AMH mutations usually show low or undetectable serum AMH levels compared to normal or elevated serum AMH levels found in cases with AMHR2 mutations"
    explanation: >-
      States the elevated as well as normal end of the receptor-subtype range,
      contrasted directly against the ligand subtype.
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum AMH and inhibin B were normal."
    explanation: >-
      A worked case in which normal serum AMH accompanied a homozygous
      likely-pathogenic AMHR2 variant.
  readouts:
  - target: Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme
    relationship: READOUT_OF
    direction: PRESENT_ABSENT
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      A normal or elevated serum AMH alongside retained Mullerian structures
      demonstrates that ligand is present and the lesion is downstream of it, at
      the receptor, and directs sequencing to AMHR2.
    evidence:
    - reference: PMID:8895659
      reference_title: "Genetic analysis of the Müllerian-inhibiting substance signal transduction pathway in mammalian sexual differentiation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "They express both MIS mRNA and protein, showing that ligand was present, but target organs were hormone-insensitive."
      explanation: >-
        The receptor-mutant mouse makes the inference explicit: measurable
        ligand with unresponsive target tissue localizes the lesion to the
        receptor.
genetic:
- name: AMH
  gene_term:
    preferred_term: AMH
    term:
      id: hgnc:464
      label: AMH
  relationship_type: CAUSATIVE
  subtype: PMDS type I
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Case 1 carried a homozygous 4-bp deletion; c.321_324del:p.Q109Lfs*29 in exon 1 of AMH (NM_000479 transcript), which is a frameshift mutation, leading to the loss of function of AMH."
      explanation: >-
        A homozygous AMH loss-of-function genotype in an affected patient,
        consistent with recessive inheritance at this locus.
  notes: >-
    AMH encodes anti-Mullerian hormone, the TGF-beta family ligand secreted by
    fetal Sertoli cells. Biallelic loss-of-function variants cause PMDS type I.
    Reported alleles are highly diverse and cluster in exons 1, 2 and 5.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Up to January 2019, 81 families with 65 different mutations of the AMH gene, mostly in exons 1, 2 and 5, have been identified."
    explanation: >-
      Documents the AMH allelic spectrum and its exon distribution.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Case 1 carried a homozygous 4-bp deletion; c.321_324del:p.Q109Lfs*29 in exon 1 of AMH (NM_000479 transcript), which is a frameshift mutation, leading to the loss of function of AMH."
    explanation: >-
      A specific biallelic loss-of-function AMH variant in a molecularly
      diagnosed PMDS patient.
- name: AMHR2
  gene_term:
    preferred_term: AMHR2
    term:
      id: hgnc:465
      label: AMHR2
  relationship_type: CAUSATIVE
  subtype: PMDS type II
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Case 2 carried compound heterozygous mutations; c.494_502del (p.I165_A168delinsT) in exon 4 and g.6147C>A of AMHR2 (NM_001164690 transcript)."
      explanation: >-
        A compound heterozygous AMHR2 genotype in an affected patient,
        consistent with recessive inheritance at this locus.
  notes: >-
    AMHR2 encodes the AMH type II serine/threonine kinase receptor expressed on
    the mesenchyme surrounding the Mullerian ducts. Biallelic loss-of-function
    variants cause PMDS type II. A recurrent 27-bp deletion in the kinase domain
    is the single commonest allele. Whole-gene and multi-exon deletions occur and
    can be missed by Sanger sequencing alone, which can make a hemizygous
    deletion look homozygous.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AMHR2 gene mutations comprising 64 different alleles have been discovered in 79 families."
    explanation: >-
      Documents the AMHR2 allelic spectrum across reported families.
  - reference: PMID:8872466
    reference_title: "A 27 base-pair deletion of the anti-müllerian type II receptor gene is the most common cause of the persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Whereas AMH mutations are extremely diverse, patients from 10 out of 16 families with receptor mutations had a 27 bp deletion in exon 10 on at least one allele."
    explanation: >-
      Establishes the recurrent 27-bp kinase-domain deletion as the commonest
      receptor allele.
  - reference: PMID:32187366
    reference_title: "Persistent Müllerian duct syndrome due to anti-Müllerian hormone receptor 2 microdeletions: a diagnostic challenge."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The patient's paternal allele carried a stop mutation, which was initially thought to be homozygous by Sanger sequencing."
    explanation: >-
      Documents the specific diagnostic pitfall in which an AMHR2 whole-gene
      deletion in trans makes a point variant appear homozygous.
- name: Unexplained PMDS (no AMH or AMHR2 variant identified)
  relationship_type: UNKNOWN
  notes: >-
    Roughly one case in eight has no identified variant in either AMH or AMHR2
    despite a clinically unambiguous phenotype. These cases are labelled
    idiopathic; the implication is that at least one further component of the
    Mullerian regression pathway remains to be identified in humans.

    Two kinds of candidate should be kept apart. PPP1R12A is the only one with a
    reported human PMDS finding - truncating variants in five of twenty-four
    patients screened after AMH and AMHR2 were excluded - and it has its own
    record in this section, typed UNKNOWN because the finding is unvalidated.
    The shared type I receptors and the SMADs are a different class of
    candidate: established in mouse, biologically obvious, and not yet reported
    as a human PMDS cause at all.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In 12% of cases, no mutation of AMH or AMHR2 has been detected, suggesting a disruption of other pathways involved in Müllerian regression."
    explanation: >-
      Quantifies the molecularly unexplained fraction and draws the same
      inference about additional pathway components.
- name: PPP1R12A
  gene_term:
    preferred_term: PPP1R12A
    term:
      id: hgnc:7618
      label: PPP1R12A
  relationship_type: UNKNOWN
  association: >-
    Reported candidate gene for molecularly unexplained PMDS; truncating variants
    found in patients but not yet functionally validated or classified for
    gene-disease validity.
  notes: >-
    PPP1R12A encodes the regulatory subunit of myosin phosphatase. Exome
    sequencing of 24 PMDS patients in whom biallelic AMH and AMHR2 variants had
    been excluded found deleterious truncating PPP1R12A variants in five, four of
    whom also had an intestinal or oesophageal atresia - a co-occurrence never
    reported with AMH or AMHR2 variants, and the argument the authors make
    against chance. This is the only gene beyond AMH and AMHR2 with a reported
    human PMDS finding, so it is recorded here rather than left out of the
    unexplained fraction.

    The claim is deliberately typed UNKNOWN rather than CAUSATIVE, and the hedge
    should be carried wherever this record is reused. There is no experimental
    validation of a role for myosin phosphatase in Mullerian regression; the
    mechanistic argument is circumstantial (myosin phosphatase is required for
    cell motility, which regression depends on) and an alternative reading, that
    the variants act on AMH signal transduction rather than beside it, is not
    excluded. PPP1R12A should not displace AMH and AMHR2 as first-line testing.
  evidence:
  - reference: PMID:36331510
    reference_title: "Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Five patients out of 24 (21%) harbored deleterious truncation mutations of PP1R12A, the gene coding for the regulatory subunit of myosin phosphatase, were detected."
    explanation: >-
      The primary human finding: truncating variants in five of twenty-four
      patients screened after AMH and AMHR2 had been excluded. (The source's
      typographical "PP1R12A" and its non-agreeing sentence are reproduced
      verbatim.)
  - reference: PMID:36331510
    reference_title: "Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In addition to PMDS, three of these patients presented with ileal and one with esophageal atresia."
    explanation: >-
      The associated malformations that the authors use to argue the finding is
      not chance, since they are not seen with AMH or AMHR2 variants.
  - reference: PMID:36331510
    reference_title: "Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The main limitation of the study is the lack of experimental validation of the role of PPP1R12A in Müllerian regression."
    explanation: >-
      The authors' own statement of the limitation, which is why this record is
      typed UNKNOWN rather than CAUSATIVE.
  - reference: PMID:36331510
    reference_title: "Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "DNA samples from 39 PMDS patients collected from 1990 to present, in which Sanger sequencing had failed to detect biallelic AMH or AMHR2 mutations, were screened by massive parallel sequencing."
    explanation: >-
      Establishes that the cohort was ascertained as AMH/AMHR2-negative, so this
      is a finding within the unexplained fraction rather than a competing
      explanation for typical PMDS.
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The detection of PPP1R12A truncation mutations coding myosin phosphatase in five cases of PMDS suggests that myosin phosphatase is involved in Müllerian regression, independently of the AMH signaling cascade"
    explanation: >-
      An independent review restating the finding, and preserving the same
      hedge - "suggests" - rather than asserting causation.
diagnosis:
- name: Diagnostic Laparoscopy
  description: >-
    Laparoscopy for impalpable or bilaterally undescended testes is the point at
    which most cases are recognized, because it is the only investigation that
    directly visualizes the retained uterus and tubes alongside the gonads. It is
    therefore both the commonest route to diagnosis and, when the finding is not
    recognized for what it is, the commonest route to a reflexive excision.
    Finding Mullerian and Wolffian derivatives together should stop the operation
    and prompt gonadal biopsy and karyotype, since other 46,XY differences of sex
    development can present the same way.
  diagnosis_term:
    preferred_term: diagnostic laparoscopy for impalpable testes
    term:
      id: NCIT:C16969
      label: Laparoscopy
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnostic laparoscopy for impalpable testes at age 6 months revealed bilateral intra-abdominal testes, with normal and expected testicular structure and appearance."
    explanation: >-
      A worked case in which laparoscopy for impalpable testes was the
      investigation that established the internal anatomy.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "With investigative laparoscopy for impalpable testes now commonplace, the recognition of FT PMDS in infancy has increased"
    explanation: >-
      Attributes the rise in infant diagnosis to routine laparoscopy, which is
      why this is the primary diagnostic route rather than an adjunct.
- name: Inguinoscrotal and Pelvic Ultrasound
  description: >-
    First-line imaging for the undescended or impalpable testis, and the study
    that most often raises the question. Its negative predictive value for the
    Mullerian remnant is poor: an ultrasound that locates neither testis and
    reports no pelvic abnormality does not exclude PMDS, and the diagnosis is
    still made at laparoscopy. Ultrasound is more useful afterwards, as the
    routine modality for annual surveillance of a preserved remnant.
  diagnosis_term:
    preferred_term: inguinoscrotal and pelvic ultrasound
    term:
      id: NCIT:C17230
      label: Ultrasound Imaging
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Initial ultrasound scan of the scrotum and pelvis did not identify the testes and did not detect any pelvic abnormality."
    explanation: >-
      A negative ultrasound in a patient subsequently shown at laparoscopy to
      have intra-abdominal testes and a Mullerian remnant, which is the
      limitation this record records.
- name: Pelvic Magnetic Resonance Imaging
  description: >-
    Cross-sectional imaging to map the retained uterus, tubes and upper vagina
    and to locate the testes before an operation is planned. The reported failure
    mode is not the scan but the request: in a series in which pelvic MRI was
    performed before surgery, the uterus went unreported in two of three
    patients, and the recommendation that follows is to tell the reporting
    radiologist that Mullerian remnants are suspected.
  diagnosis_term:
    preferred_term: pelvic magnetic resonance imaging
    term:
      id: NCIT:C16809
      label: Magnetic Resonance Imaging
  evidence:
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "They were furtherly diagnosed with PMDS, as pelvic magnetic resonance imaging revealed the presence of Müllerian remnants."
    explanation: >-
      Pelvic MRI is the study that confirmed the Mullerian remnants in all three
      molecularly diagnosed patients in this series.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In this study, two of the three patients (cases 1 and 2) underwent pelvic MRI before surgery in a local hospital, but the presence of a uterus was not reported in either of them."
    explanation: >-
      Documents the reporting failure that motivates naming the suspicion on the
      request form, rather than treating a normal MRI report as exclusion.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "For patients with suspected PMDS, preoperative AMH hormone examination, genetic analysis, and MRI after informing the imaging physician of possible uterine remnants can improve the diagnosis rate of PMDS."
    explanation: >-
      States the combined preoperative pathway - hormone measurement, genetics
      and a forewarned MRI - that this diagnosis section models.
- name: Karyotype
  description: >-
    Chromosome analysis, expected to show 46,XY. It does not diagnose PMDS, and a
    normal male karyotype is compatible with several other 46,XY differences of
    sex development. Its role is to place the patient in the right diagnostic
    frame before an irreversible operation, and to give the family an answer at
    the point where an unexpected uterus has been found.
  diagnosis_term:
    preferred_term: karyotype analysis
    term:
      id: NCIT:C16768
      label: Karyotyping
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gonadal biopsy and karyotype before proceeding to orchidopexy will help to give the family time to understand the condition, to get reassurance about the karyotype, and to get objective reassurance about the presence of normal testicular tissue."
    explanation: >-
      States the sequencing rationale curated here: karyotype before the
      definitive operation rather than after it.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The patient had the normal 46, XY karyotype."
    explanation: >-
      The expected result in a molecularly confirmed patient, establishing the
      karyotype as normal rather than diagnostic.
- name: Serum Anti-Mullerian Hormone with Gonadotropin and Androgen Panel
  description: >-
    Serum AMH, measured alongside inhibin B, testosterone, LH and FSH. AMH
    partitions the two genetic subtypes rather than establishing the diagnosis: a
    low or undetectable value points to the ligand gene and a normal or elevated
    value to the receptor gene. A normal AMH therefore does not exclude PMDS, and
    reading it that way is one of the routes to a missed diagnosis. Tumour
    markers are added when a mass is present.
  diagnosis_term:
    preferred_term: serum anti-Mullerian hormone measurement
    term:
      id: NCIT:C120625
      label: Anti-Mullerian Hormone Measurement
  results: >-
    Low or undetectable serum AMH in PMDS type I; normal or elevated serum AMH in
    PMDS type II.
  notes: >-
    The two directions are curated as separate subtype-attributed records in the
    biochemical section, where the discrepancy between them is the informative
    content.
  evidence:
  - reference: PMID:39682529
    reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum AMH and inhibin B were normal."
    explanation: >-
      A normal AMH and inhibin B in a patient subsequently shown to carry a
      biallelic AMHR2 variant, which is the receptor-subtype pattern.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "He was diagnosed with azoospermia after hormone analysis"
    explanation: >-
      Places the gonadotropin and androgen panel in the workup of the adult
      infertility presentation, which is where PMDS is often first suspected.
- name: AMH and AMHR2 Sequencing with Copy-Number Analysis
  description: >-
    Sequence and deletion/duplication analysis of both genes. Copy-number
    detection is specified rather than assumed because AMHR2 microdeletions
    occur, and a whole-gene deletion in trans with a point variant makes that
    variant look homozygous on Sanger sequencing alone - so a sequencing-only
    result can be both wrong about zygosity and wrong about which parent is a
    carrier. A wider disorder-of-sex-development panel or exome is appropriate
    when first-line testing is negative, and a negative result does not exclude
    the pathway. After a molecular diagnosis, cascade testing is offered to
    siblings.
  diagnosis_term:
    preferred_term: AMH and AMHR2 sequencing with deletion/duplication analysis
    term:
      id: NCIT:C15709
      label: Genetic Testing
  evidence:
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Three of the 11 patients had biallelic mutations in AMH or AMHR2."
    explanation: >-
      The diagnostic yield of sequencing in an unselected cryptorchidism cohort,
      which is the basis for testing in selected cryptorchidism.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Copy number variants were identified using the DNA copy R package, filtered and classified by ACMG guidelines, and manually checked using the Integrative Genomics Viewer."
    explanation: >-
      Records copy-number calling as part of the analysis rather than an
      optional add-on.
  - reference: PMID:32187366
    reference_title: "Persistent Müllerian duct syndrome due to anti-Müllerian hormone receptor 2 microdeletions: a diagnostic challenge."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report the first cases of PMDS resulting from a microdeletion of the chromosomal region 12q13.13, the locus of the gene for AMHR2."
    explanation: >-
      Establishes that AMHR2 copy-number variants cause PMDS, so an assay blind
      to them can miss the diagnosis outright.
  - reference: PMID:32187366
    reference_title: "Persistent Müllerian duct syndrome due to anti-Müllerian hormone receptor 2 microdeletions: a diagnostic challenge."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnostic methods are discussed, with an emphasis on comparative genomic hybridization and targeted massive parallel sequencing."
    explanation: >-
      The authors' own methodological conclusion, which is why copy-number
      analysis is written into this record rather than left implicit.
- name: Histopathological Examination of Gonadal and Mullerian Tissue
  description: >-
    Histology of the gonadal biopsy and of any excised remnant. The biopsy
    confirms normal testicular tissue, which is what separates PMDS from the
    gonadal dysgenesis differentials; examination of the remnant confirms
    Mullerian epithelium and smooth muscle and is the point at which
    unsuspected malignancy would be found.
  diagnosis_term:
    preferred_term: histopathological examination of gonadal and Mullerian tissue
    term:
      id: NCIT:C18190
      label: Histopathologic Examination
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Histology of bilateral gonadal biopsy showed normal testicular tissue."
    explanation: >-
      The expected gonadal result, which is the finding that excludes gonadal
      dysgenesis.
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The patient was histologically confirmed to have PMDS"
    explanation: >-
      Histology of the excised remnant as the confirmatory step in a
      molecularly diagnosed patient.
- name: Semen Analysis
  description: >-
    Assessment of the ejaculate in an adult, and the first step of the fertility
    workup. Where the excurrent ducts are intact and at least one testis is
    scrotal, spontaneous paternity is possible, so the result decides whether
    sperm can be banked from the ejaculate or must be sought by testicular
    extraction. Azoospermia is reported in adults presenting with infertility,
    and in some men the reproductive workup is the route by which the syndrome
    is first recognized.
  diagnosis_term:
    preferred_term: semen analysis
    term:
      id: NCIT:C25294
      label: Laboratory Procedure
  evidence:
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "came to our medical center for routine semen analysis"
    explanation: >-
      Semen analysis as the entry point to the reproductive workup in an adult
      later diagnosed with PMDS.
  - reference: PMID:33532339
    reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Semen analysis showed both patients were azoospermic."
    explanation: >-
      The result semen analysis returned in two adult PMDS cases presenting
      with infertility.
  notes: >-
    No NCIT term is labelled "semen analysis"; an OLS search of NCIT for
    "semen analysis" returned nothing. NCIT:C74663 Spermatozoa Cell Count is
    reachable from Clinical Intervention or Procedure but names only one
    component of the analysis, so the parent Laboratory Procedure is bound and
    the specificity is carried in preferred_term.
treatments:
- name: Orchidopexy
  description: >-
    Placement of the malpositioned testes into the scrotum, staged
    (Fowler-Stephens) when the gonadal vessels are too short. Performed early in
    childhood, this is the intervention that addresses both fertility potential
    and germ cell tumour risk, and it takes priority over management of the
    Mullerian remnant.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Orchiopexy
    term:
      id: NCIT:C111066
      label: Orchiopexy
  target_mechanisms:
  - target: Mechanical Tethering of the Testis by Retained Mullerian Structures
    description: >-
      Surgical mobilization overcomes the mechanical restraint the retained
      structures impose on descent.
    evidence:
    - reference: PMID:35386545
      reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Both intra-abdominal testes were successfully moved to an intrascrotal position with the vasa and vasal blood supply intact."
      explanation: >-
        Shows the operation achieving intrascrotal placement despite the tether,
        which is the mechanism this treatment targets.
  - target: Germ Cell Neoplasia Risk in the Malpositioned Testis
    description: >-
      Bringing the testis to a palpable scrotal position reduces malignancy risk
      and makes surveillance by examination possible.
    evidence:
    - reference: PMID:35386545
      reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Early orchidopexy should be offered to children with PMDS."
      explanation: >-
        Recommends early orchidopexy for PMDS specifically, on the malignancy
        risk-reduction rationale this mechanism link asserts.
  evidence:
  - reference: PMID:9187705
    reference_title: "Surgical management of persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Optimal surgical management is orchiopexy leaving the uterus and fallopian tubes in situ."
    explanation: >-
      Names orchidopexy as the primary operation in a comprehensive review of
      PMDS surgical management.
- name: Preservation of Mullerian Remnants and the Vas Deferens
  description: >-
    The vasa deferentia and their blood supply run in the wall of the retained
    Mullerian structures, so aggressive excision of the remnant risks
    sterilizing the patient and devascularizing the testis. The recommended
    default is therefore to leave the uterus and tubes in situ, or to split the
    remnant sagittally to gain length for descent, rather than to excise it. This
    trades a small ongoing malignancy risk in the remnant, managed by
    surveillance, against a large and immediate iatrogenic fertility risk. Where
    excision is unavoidable, subtotal hysterectomy with deliberate preservation
    of the vasa is the compromise.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Mullerian-remnant-sparing surgical technique
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  target_mechanisms:
  - target: Impaired Spermatogenesis and Excurrent Duct Compromise
    description: >-
      Sparing the remnant avoids the iatrogenic component of excurrent duct and
      testicular vascular injury.
    evidence:
    - reference: PMID:9187705
      reference_title: "Surgical management of persistent müllerian duct syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Surgical excision of persistent müllerian duct structure may result in ischemic and/or traumatic damage to the vasa deferentia and testes."
      explanation: >-
        States the specific harm the sparing technique is designed to avoid,
        which is the mechanism this treatment targets.
  evidence:
  - reference: PMID:9187705
    reference_title: "Surgical management of persistent müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Meticulous proximal salpingectomy and hysterectomy is indicated only in patients whose müllerian structures limit intrascrotal placement of the tests."
    explanation: >-
      Restricts excision to the case where the remnant blocks descent,
      establishing preservation as the default. (The source's typographical
      "tests" for "testes" is reproduced verbatim.)
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Müllerian remnant was preserved to maintain testicular vascularity."
    explanation: >-
      A worked case in which the remnant was deliberately left in situ for
      vascular preservation.
  - reference: PMID:26246705
    reference_title: "Persistent Müllerian Duct Syndrome (PMDS): a Rare Anomaly the General Surgeon Must Know About."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Both patients intraoperatively had uterus with fallopian tubes and underwent subtotal hysterectomy with preservation of vas."
    explanation: >-
      Illustrates the subtotal-excision compromise, in which the vas is
      deliberately spared.
- name: Excision of Mullerian Remnants
  description: >-
    Hysterectomy with proximal salpingectomy, removing the retained structures.
    Reserved for cases where the remnant prevents intrascrotal placement of the
    testis, or is symptomatic, and used more often in adults, where the
    remaining fertility to protect is smaller and cumulative malignancy exposure
    is longer. It is not the default in children.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Hysterectomy with proximal salpingectomy of Mullerian remnants
    term:
      id: NCIT:C15256
      label: Hysterectomy
  target_mechanisms:
  - target: Neoplastic Transformation of Retained Mullerian Epithelium
    description: >-
      Removing the epithelium removes the tissue at risk of malignant change.
    evidence:
    - reference: PMID:26246705
      reference_title: "Persistent Müllerian Duct Syndrome (PMDS): a Rare Anomaly the General Surgeon Must Know About."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Early treatment is needed to maintain fertility and to prevent the occurrence of malignancy in remnant müllerian structures."
      explanation: >-
        States prevention of remnant malignancy as the goal of removing the
        structures, which is the mechanism this treatment targets.
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "in other reports, the Mullerian structures are excised, especially in adults"
    explanation: >-
      Records excision as a used option and its skew toward adult patients.
- name: Inguinal Hernia Repair
  description: >-
    Repair of the associated inguinal hernia, frequently the operation at which
    PMDS is first recognized. Recognizing Mullerian structures in the sac should
    stop reflexive excision and prompt karyotype, gonadal biopsy and endocrine
    assessment before further surgery.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Herniorrhaphy
    term:
      id: NCIT:C168249
      label: Herniorrhaphy
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The main surgical considerations are repairing associated inguinal hernias; preserving gonadal function and fertility and minimising the risk of malignant change by early orchidopexy and careful preservation of gonadal vasculature and vasal and ductal structures; and long-term surveillance for potential malignancy in pexed testes and retained Müllerian structures."
    explanation: >-
      Lists hernia repair first among the surgical considerations in PMDS.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gonadal biopsy and karyotype before proceeding to orchidopexy will help to give the family time to understand the condition, to get reassurance about the karyotype, and to get objective reassurance about the presence of normal testicular tissue."
    explanation: >-
      Supports pausing for karyotype and biopsy once Mullerian structures are
      found intraoperatively.
- name: Long-term Surveillance of Preserved Mullerian Remnants and Pexed Testes
  description: >-
    Where the remnant is left in situ, annual ultrasound with periodic MRI is
    used to watch for growth or a new mass, alongside examination of the pexed
    testes. There is no evidence base establishing either the optimal modality
    or the interval; the practice follows from the malignancy risk rather than
    from trial data, and that uncertainty should be stated to families.
  action_category: MONITORING
  treatment_term:
    preferred_term: Imaging surveillance of retained Mullerian structures
    term:
      id: NCIT:C17230
      label: Ultrasound Imaging
  evidence:
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "If the Müllerian remnant is left in situ, the literature advocates regular ultrasound surveillance, such as annually, to assess for change in size or new mass lesions"
    explanation: >-
      States the surveillance practice for a preserved remnant.
  - reference: PMID:35386545
    reference_title: "Persistent Müllerian Duct Syndrome: Understanding the Challenges."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "At present, there is no data to suggest whether one modality is superior for surveillance purposes, and there is no data to guide the frequency of surveillance should it be undertaken."
    explanation: >-
      Records the absence of an evidence base for modality or interval, which is
      the caveat curated in this treatment's description.
- name: Sperm Cryopreservation
  description: >-
    Banking of any sperm recovered from the ejaculate, once semen analysis (see
    diagnosis) shows that sperm are present. Banking before any further Mullerian
    or inguinal surgery matters because the vasa run in the wall of the remnant
    and each operation carries its own risk of obstructing them.
  action_category: THERAPEUTIC
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: sperm cryopreservation
    term:
      id: NCIT:C16475
      label: Cryopreservation
  target_mechanisms:
  - target: Impaired Spermatogenesis and Excurrent Duct Compromise
    description: >-
      Banking sperm while they are still obtainable preserves reproductive
      options against the progressive and iatrogenic components of this
      mechanism, without altering the mechanism itself.
    evidence:
    - reference: PMID:39682529
      reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The mechanisms involved are cryptorchidism and late orchidopexy, male excretory duct anomalies, and iatrogenic lesions."
      explanation: >-
        Names the iatrogenic and progressive components of the infertility that
        banking before further surgery is intended to outrun.
  evidence:
  - reference: PMID:33532339
    reference_title: "Transverse testicular ectopia associated with persistent Mullerian duct syndrome in infertile male: two case reports and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We intended to cryopreserve sperms, however, both patients were azoospermic."
    explanation: >-
      Sperm banking planned at the time of surgery in adult PMDS, and the
      dependence of that plan on the semen-analysis result.
  notes: >-
    NCIT has no term labelled "sperm cryopreservation" reachable from Clinical
    Intervention or Procedure (NCIT:C25218), so the generic Cryopreservation action is bound and the specificity is carried in
    preferred_term.
- name: Testicular Sperm Extraction
  description: >-
    Microdissection testicular sperm extraction (micro-TESE) in men with
    azoospermia, to recover spermatozoa directly from the testis when none reach
    the ejaculate. This is the intervention that addresses the excurrent-duct
    limb of the infertility, since sperm may be produced but unable to leave.
    Reported success is roughly one man in two, comparable to non-obstructive
    azoospermia without PMDS, so a negative result is common and should be
    anticipated in counselling.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: microdissection testicular sperm extraction
    term:
      id: NCIT:C94427
      label: Sperm Retrieval
  target_mechanisms:
  - target: Impaired Spermatogenesis and Excurrent Duct Compromise
    description: >-
      Retrieving sperm from the testis bypasses the obstructed or injured
      excurrent duct that this mechanism describes.
    evidence:
    - reference: PMID:35052499
      reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Micro-TESE was performed and sperms were observed; Müllerian remnants were removed laparoscopically."
      explanation: >-
        Sperm recovered directly from the testis in a PMDS patient who was
        azoospermic on semen analysis, which is what this treatment targets.
  evidence:
  - reference: PMID:35052499
    reference_title: "Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "No sperms in semen was observed in cases 1 and 2 of this study, and the micro-TESE success rate was 50%"
    explanation: >-
      The reported retrieval rate in this series, and the comparison with
      non-PMDS azoospermia that sets the counselling expectation.
  notes: >-
    NCIT has no term labelled "testicular sperm extraction" reachable from
    Clinical Intervention or Procedure (NCIT:C25218); the action term bound here
    is Sperm Retrieval and the technique is carried in preferred_term.
- name: Intracytoplasmic Sperm Injection
  description: >-
    Assisted fertilization using surgically retrieved sperm. It is the step that
    converts a successful extraction into a chance of biological paternity, and
    it is the only route available once the excurrent ducts are congenitally
    abnormal or have been injured during Mullerian or inguinal surgery.
  action_category: THERAPEUTIC
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: intracytoplasmic sperm injection
    term:
      id: NCIT:C185482
      label: Intracytoplasmic Sperm Injection
  target_mechanisms:
  - target: Impaired Spermatogenesis and Excurrent Duct Compromise
    description: >-
      Fertilization in vitro removes the requirement for sperm transit through
      the compromised excurrent duct entirely.
    evidence:
    - reference: PMID:39682529
      reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "If spermatogenesis is present, testicular sperm extraction followed by ICSI may be used to facilitate conception in cases of congenital or iatrogenic lesions of the male excretory ducts"
      explanation: >-
        Names both the indication - congenital or iatrogenic excretory duct
        lesions - and the extraction-plus-injection sequence this treatment
        completes.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact."
    explanation: >-
      Sets the baseline this treatment is meant to improve on: unassisted
      paternity depends on an intact excretory duct, which assisted
      fertilization does not require.
- name: Orchidectomy for a Nonviable or Malignancy-Suspicious Testis
  description: >-
    Removal of a testis that is atrophic, unsalvageable after repeated attempts
    at fixation, or carries a mass suspicious for malignancy. It is the
    counterpart to orchidopexy and not an alternative to it: the aim throughout
    is to place a viable testis in the scrotum, and orchidectomy is what remains
    once that testis has been lost. Because the malignancy risk in PMDS is
    carried by the malpositioned gonad, an intra-abdominal testis that cannot be
    brought down and cannot be examined is the situation in which the decision
    arises.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: orchidectomy of a nonviable or malignancy-suspicious testis
    term:
      id: NCIT:C15288
      label: Orchiectomy
  target_mechanisms:
  - target: Germ Cell Neoplasia Risk in the Malpositioned Testis
    description: >-
      Removing a testis that cannot be placed in the scrotum or examined
      removes the tissue that carries the germ cell tumour risk.
    evidence:
    - reference: PMID:39682529
      reference_title: "Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "In September 2021, at the age of 12, surgery was repeated on the left hemiscrotum, and a small atrophic left testicle was discovered, for which an orchidectomy was performed, taking into account the risk of malignancy."
      explanation: >-
        A worked case giving both indications together: an atrophic testis
        removed explicitly on the malignancy-risk rationale this link asserts.
  evidence:
  - reference: PMID:32172781
    reference_title: "Persistent Müllerian duct syndrome: an update."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Testicular malignant degeneration occurs in 33% of adults with PMDS."
    explanation: >-
      The malignancy burden that makes removal of an unsalvageable, unexaminable
      testis a considered option rather than an abandonment of fertility.
animal_models:
- name: Amhr2 (MIS type II receptor) mutant mouse
  species: Mouse
  genotype: Amhr2 null (MIS type II receptor mutant)
  publication: PMID:8895659
  description: >-
    Receptor-null male mice retain a uterus and oviducts alongside a complete
    male reproductive tract, phenocopying the ligand-null mouse. They produce
    sperm but are largely infertile because the retained female structures
    obstruct sperm transfer. The model reproduces the PMDS dissociation and shows
    that ligand and receptor loss converge on the same phenotype.
  modeled_mechanisms:
  - target: Failure of Mullerian Duct Regression
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: ORGANISM
    description: >-
      Genetic ablation of the AMH type II receptor in the mouse reproduces
      retention of uterus and oviducts in an otherwise male animal.
    limitations: >-
      Mouse testes descend on a different anatomical schedule from human testes,
      so the model does not reproduce the cryptorchidism and inguinal
      presentations that dominate the human clinical picture. Infertility in the
      mouse arises mechanically from obstructed sperm transfer rather than from
      the malpositioned-testis and surgical-injury routes that operate in humans.
    evidence:
    - reference: PMID:8895659
      reference_title: "Genetic analysis of the Müllerian-inhibiting substance signal transduction pathway in mammalian sexual differentiation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "MIS receptor mutant males develop as internal pseudohermaphrodites, possessing a complete male reproductive tract and also a uterus and oviducts, a phenocopy of MIS ligand-deficient male mice."
      explanation: >-
        Reports the retained Mullerian derivatives alongside an intact male
        tract, the node this model is linked to.
  evidence:
  - reference: PMID:8895659
    reference_title: "Genetic analysis of the Müllerian-inhibiting substance signal transduction pathway in mammalian sexual differentiation."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "All produce sperm, but the majority were infertile because the presence of their female reproductive organs blocks sperm transfer into females."
    explanation: >-
      Establishes the model's reproductive phenotype and the mechanical route by
      which it arises in the mouse.
- name: Mullerian-mesenchyme-specific Bmpr1a conditional knockout mouse
  species: Mouse
  genotype: Bmpr1a (Alk3) conditional knockout in Mullerian duct mesenchyme
  publication: PMID:12368913
  description: >-
    Deleting the shared type I BMP receptor Bmpr1a specifically in Mullerian duct
    mesenchyme leaves oviducts and uteri in male mice, identifying Bmpr1a as the
    type I receptor for AMH-induced regression. This is the model that
    establishes the receptor-complex step downstream of AMHR2.
  evidence:
  - reference: PMID:12368913
    reference_title: "Requirement of Bmpr1a for Müllerian duct regression during male sexual development."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Amh induces regression by binding to a specific type II receptor (Amhr2) expressed in the mesenchyme surrounding the ductal epithelium."
    explanation: >-
      Establishes that the mesenchyme this model manipulates is the AMH-receiving
      compartment, which is what makes the conditional knockout informative for
      the human receptor step.
  modeled_mechanisms:
  - target: Failed AMH Receptor Signaling in Mullerian Duct Mesenchyme
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: MOLECULAR
    description: >-
      Tissue-specific deletion isolates the type I receptor requirement within
      the periductal mesenchyme.
    limitations: >-
      BMPR1A variants have not been reported as a cause of human PMDS, so the
      model establishes the pathway architecture rather than a human disease
      gene. Type I receptor usage is partly redundant in mouse, so a single
      conditional knockout may not map cleanly onto the human requirement.
    evidence:
    - reference: PMID:12368913
      reference_title: "Requirement of Bmpr1a for Müllerian duct regression during male sexual development."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "These results identify Bmpr1a as a type I receptor for Amh-induced regression of Müllerian ducts."
      explanation: >-
        States the conclusion the model supports about the receptor complex
        annotated on this node.
- name: Canine AMHR2 p.Arg81Ter Miniature Schnauzer (naturally occurring PMDS)
  species: Dog
  genotype: AMHR2 c.241C>T (p.Arg81Ter) homozygous, sex-limited autosomal recessive
  background: Miniature Schnauzer (Canis lupus familiaris, NCBITaxon:9615)
  publication: PMID:29194807
  description: >-
    Naturally occurring, breed-enriched PMDS in the Miniature Schnauzer, caused by
    a nonsense variant in the third exon of AMHR2 that abolishes receptor
    expression. Affected males retain oviducts, uterus, uterine body, cervix and
    a cranial vagina, and about half are unilaterally or bilaterally cryptorchid.
    This is the point of the model: it reproduces the retained Mullerian
    derivatives that the mouse also reproduces, and in addition the failure of
    testicular descent that the mouse does not, so it is the only available
    whole-organism system in which the tethering step can be observed rather than
    inferred. It is a spontaneous, outbred, population-level model rather than an
    engineered one - the variant was found at an allele frequency of 0.16 among
    216 North American Miniature Schnauzers, with 27 percent carriers.
  notes: >-
    Curated in response to the HUMAN_MODEL_MISMATCH discussion in this entry,
    which argues that the dog is the better model for the mechanical-tethering
    step and proposes canine descent phenotyping as the resolving experiment.
    Sertoli-cell tumours are reported in canine PMDS in the wider veterinary
    literature, but no exactly quotable statement of that was found in the
    references cached for this entry, so the tumour claim here is kept at the
    level the sources support - increased risk of testicular tumours.
  modeled_mechanisms:
  - target: Mechanical Tethering of the Testis by Retained Mullerian Structures
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      Affected dogs carry the retained Mullerian derivatives and, unlike the
      Amh-null and Amhr2-null mouse, present with cryptorchidism, so retention
      and failed descent co-occur in one animal as they do in human PMDS.
    limitations: >-
      Cryptorchidism is reported in roughly half of affected dogs rather than in
      all of them, and canine testicular descent is not on the human schedule, so
      the co-occurrence establishes that retention and failed descent travel
      together in this species without demonstrating the tether itself. The
      allele is breed-restricted: the same study sequenced AMH and AMHR2 in a
      PMDS-affected Belgian Malinois and found no causal variant, so canine PMDS
      is not one genetic entity. The cohort is a genotyping survey, not a
      gubernacular or cord-anatomy study, and no measurement of the attachment
      between remnant and testis was made.
    readouts:
    - name: Proportion of PMDS-affected dogs that are cryptorchid
      target: Mechanical Tethering of the Testis by Retained Mullerian Structures
      direction: INCREASED
      interpretation: >-
        Failure of descent in about half of affected animals, against a low
        breed background rate, is the observation that distinguishes this model
        from the rodent models of the same pathway.
      evidence:
      - reference: PMID:29194807
        reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: "An estimated 50% of male dogs affected by PMDS are cryptorchid"
        explanation: >-
          Reports the measurement behind this readout.
    - name: Mullerian derivatives retained in affected males
      target: Mechanical Tethering of the Testis by Retained Mullerian Structures
      direction: INCREASED
      interpretation: >-
        The retained structures are present and anatomically continuous with the
        male tract, which is the substrate the tether requires.
      evidence:
      - reference: PMID:29194807
        reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: "Affected males can have oviducts, a uterus, uterine body, cervix, and even a cranial vagina that enters into the prostate"
        explanation: >-
          Records the retained derivatives in affected dogs, the anatomical
          finding this readout measures.
    evidence:
    - reference: PMID:29194807
      reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "An important consequence of this syndrome is bilateral or unilateral cryptorchidism, which often occurs in PMDS-affected dogs and causes infertility as well as increased risk for testicular tumors"
      explanation: >-
        Establishes that in the dog the retained Mullerian structures and failed
        descent occur together and carry the same downstream consequences as in
        human PMDS, which is what makes this model informative for the tethering
        node.
  evidence:
  - reference: PMID:29194807
    reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "The genetic basis for PMDS in Miniature Schnauzers is a sex-limited autosomal recessive C to T transition (c.241C>T; p.R81*) nonsense mutation in the third exon of the AMHR2 gene"
    explanation: >-
      Names the causal allele and its inheritance, establishing that the canine
      lesion is in the same gene as human PMDS type II.
  - reference: PMID:29194807
    reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "As a result, AMHR2 is not expressed, and the Müllerian ducts fail to regress in affected males."
    explanation: >-
      States the molecular consequence, matching the receptor-loss step curated
      at the head of this entry's pathograph.
  - reference: PMID:29194807
    reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "The Miniature Schnauzer cohort had an AMHR2 mutation allele frequency of 0.16 and a carrier genotypic frequency of 0.27."
    explanation: >-
      Quantifies how common the allele is in the breed, which is what makes the
      model practically available rather than a single case report.
  - reference: PMID:29194807
    reference_title: "Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "The genetic basis for PMDS in the Belgian Malinois was not determined, as no coding or splicing mutations were identified in either AMH or AMHR2."
    explanation: >-
      A negative result in a second breed, recording that canine PMDS is not a
      single genetic entity and bounding what this model generalizes to.
discussions:
- discussion_id: pmds_mouse_model_lacks_descent_phenotype
  kind: HUMAN_MODEL_MISMATCH
  attaches_to:
  - pathophysiology#Mechanical Tethering of the Testis by Retained Mullerian Structures
  prompt: >-
    Does the mouse AMH-pathway knockout, which retains Mullerian derivatives
    without the cryptorchidism that dominates human PMDS, model the mechanical
    tethering step at all?
  rationale: >-
    The Amh-null and Amhr2-null mouse faithfully reproduces the retained uterus
    and oviducts, but mouse testes are not scrotal on the human schedule and the
    knockouts are not reported as cryptorchid. The single most clinically
    consequential step in human PMDS - the retained structures physically
    preventing testicular descent, and thereby generating the cryptorchidism,
    hernia, ectopia, malignancy risk and infertility that bring patients to
    surgery - is therefore not observable in the standard rodent model. The
    human evidence for it is inference from operative anatomy rather than
    experiment. The dog, in which spontaneous AMHR2-related PMDS does present
    with undescended testes, is the better model for this specific step.
  proposed_experiments:
  - experiment_id: canine_amhr2_descent_phenotyping
    name: Comparative gubernacular and descent phenotyping in canine AMHR2-related PMDS
    description: >-
      Characterize gubernacular attachment, cord anatomy and testicular position
      in dogs with naturally occurring AMHR2-related PMDS against unaffected
      littermates, to test whether the retained Mullerian structures are the
      physical constraint on descent rather than a co-occurring finding.
    readouts:
    - name: Testicular position relative to the inguinal ring
      target: pathophysiology#Mechanical Tethering of the Testis by Retained Mullerian Structures
      direction: ALTERED
      interpretation: >-
        A tether-dependent constraint predicts that testicular position tracks
        the extent and attachment of the retained structures.
notes: >-
  Positioning against the other disorders of sex development already in the
  knowledge base. PMDS is not a gonadal dysgenesis and should not be grouped with
  the 46,XY gonadal dysgenesis entries: the gonads are histologically normal
  testes, they secrete testosterone normally, and external virilization is
  complete. Nor is it an androgen-pathway disorder like androgen insensitivity or
  5-alpha-reductase 2 deficiency, in which the testis is normal but the
  testosterone or dihydrotestosterone arm fails and external masculinization is
  incomplete. PMDS is the mirror image of those conditions: the androgen arm is
  intact and the AMH arm alone is broken. This one-arm lesion is what makes the
  entry mechanistically distinctive and is the reason the preserved Leydig-cell
  node is curated explicitly rather than left implicit.

  No mechanism module in kb/modules/ was a genuine fit for the AMH ligand-receptor
  failure, so no conforms_to is declared. The nearest candidates were checked and
  rejected: aortopathy_tgfbeta_dysregulation concerns excess TGF-beta signaling
  in the aortic wall rather than loss of a TGF-beta family ligand-receptor pair,
  and the serial-homology modules cover repeated developmental elements rather
  than a single hormone-dependent regression event.

  Two findings from the deep-research report were deliberately not curated. A
  series in which three of eight patients developed cysts in a preserved
  Mullerian remnant would pair naturally with the remnant-preservation treatment
  modelled here, but no exactly quotable statement of it exists in any reference
  cached for this entry, and the report attributes it to a page range of a review
  whose cached full text does not contain the word. Sertoli-cell tumours in
  canine PMDS are likewise reported in the wider veterinary literature but not
  quotable from the cached canine reference, so the animal-model record states
  increased testicular tumour risk instead. Both are recorded here so a later
  curator can fetch a primary source rather than rediscover the gap.

  The remnant-preservation treatment is bound to the generic NCIT Surgical
  Procedure term (NCIT:C15329) on purpose. The intervention is defined by what it
  leaves behind rather than by what it removes, and NCIT was searched without
  finding a clinical-action term for operating around a structure while
  preserving it; a more specific term naming an excision would misstate the
  treatment.

  Retained Fallopian tubes are curated inside the "Presence of Uterus in 46,XY
  Individual" phenotype rather than as a separate phenotype, because HPO has no
  term for the presence of Fallopian tubes in a 46,XY individual and the
  available fallopian-tube terms all code morphological abnormality, which is not
  what is being asserted.

  Serum AMH is curated as two subtype-attributed biochemical records rather than
  one, because the informative content is the discrepancy between them: a low
  value points to the ligand gene and a normal value to the receptor gene, and a
  single record could not carry both. Note that a normal serum AMH does not
  exclude PMDS.

📚

References & Deep Research

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (2)

Record notes

Positioning against the other disorders of sex development already in the knowledge base. PMDS is not a gonadal dysgenesis and should not be grouped with the 46,XY gonadal dysgenesis entries: the gonads are histologically normal testes, they secrete testosterone normally, and external virilization is complete. Nor is it an androgen-pathway disorder like androgen insensitivity or 5-alpha-reductase 2 deficiency, in which the testis is normal but the testosterone or dihydrotestosterone arm fails and external masculinization is incomplete. PMDS is the mirror image of those conditions: the androgen arm is intact and the AMH arm alone is broken. This one-arm lesion is what makes the entry mechanistically distinctive and is the reason the preserved Leydig-cell node is curated explicitly rather than left implicit. No mechanism module in kb/modules/ was a genuine fit for the AMH ligand-receptor failure, so no conforms_to is declared. The nearest candidates were checked and rejected: aortopathy_tgfbeta_dysregulation concerns excess TGF-beta signaling in the aortic wall rather than loss of a TGF-beta family ligand-receptor pair, and the serial-homology modules cover repeated developmental elements rather than a single hormone-dependent regression event. Two findings from the deep-research report were deliberately not curated. A series in which three of eight patients developed cysts in a preserved Mullerian remnant would pair naturally with the remnant-preservation treatment modelled here, but no exactly quotable statement of it exists in any reference cached for this entry, and the report attributes it to a page range of a review whose cached full text does not contain the word. Sertoli-cell tumours in canine PMDS are likewise reported in the wider veterinary literature but not quotable from the cached canine reference, so the animal-model record states increased testicular tumour risk instead. Both are recorded here so a later curator can fetch a primary source rather than rediscover the gap. The remnant-preservation treatment is bound to the generic NCIT Surgical Procedure term (NCIT:C15329) on purpose. The intervention is defined by what it leaves behind rather than by what it removes, and NCIT was searched without finding a clinical-action term for operating around a structure while preserving it; a more specific term naming an excision would misstate the treatment. Retained Fallopian tubes are curated inside the "Presence of Uterus in 46,XY Individual" phenotype rather than as a separate phenotype, because HPO has no term for the presence of Fallopian tubes in a 46,XY individual and the available fallopian-tube terms all code morphological abnormality, which is not what is being asserted. Serum AMH is curated as two subtype-attributed biochemical records rather than one, because the informative content is the discrepancy between them: a low value points to the ligand gene and a normal value to the receptor gene, and a single record could not carry both. Note that a normal serum AMH does not exclude PMDS.

Create: Persistent_Mullerian_Duct_Syndrome · 2026-09-05T20:25:39Z · View source

De novo curation of persistent Mullerian duct syndrome (MONDO:0009857) as a DISEASE entry with two has_subtypes, replacing the stub of the same name. What was curated. 10 pathophysiology nodes forming a single causal chain from biallelic AMH/AMHR2 loss of function, through failed AMH receptor signalling in Mullerian duct mesenchyme (AMHR2 plus a shared type I BMP receptor plus SMADs), to failure of Mullerian duct regression, and from there to mechanical tethering of the testis, germ cell neoplasia risk in the malpositioned testis, neoplastic transformation of retained Mullerian epithelium, impaired spermatogenesis, and delayed incidental diagnosis. A separate two-node branch curates the preserved Leydig-cell androgen arm and normal Wolffian/external virilization, because the dissociation between the broken AMH arm and the intact androgen arm is the defining feature of the disease and is what separates it from gonadal dysgenesis. Cryptorchidism, inguinal hernia and transverse testicular ectopia are drawn as causal consequences of the tether, not as co-occurring findings. 9 phenotypes, 5 treatments, 2 biochemical records, 3 genetic records, 2 has_subtypes, 2 animal models, 1 HUMAN_MODEL_MISMATCH discussion, 90 evidence items over 17 references. Subtypes and the serum-AMH signature. PMDS type I (AMH ligand, hgnc:464) and PMDS type II (AMHR2 receptor, hgnc:465), each bound to its NCIT subtype term and each carrying its gene. The serum AMH discrepancy that distinguishes them is curated as two subtype-attributed biochemical records with BiomarkerReadout links into the pathograph rather than as prose: low or undetectable AMH reads out the ligand defect, normal or elevated AMH reads out the receptor defect with ligand demonstrably present. A third genetic record covers the roughly 12 percent of cases with a variant in neither gene. Surgical trade-off. The orchidopexy / remnant-preservation / remnant-excision treatments are curated as three distinct entries with opposing target_mechanisms, so that the reason preservation is the default (the vasa deferentia run in the wall of the retained structures, and excision risks sterilizing the patient) is machine-readable rather than buried in prose. Deep research. One falcon (Edison Scientific) run, research/Persistent_Mullerian_Duct_Syndrome-deep-research-falcon.md. Its reference validation reported 5/5 references resolved and its term validation 20/22 resolved with needs_review true; the single mislabelled term was the template placeholder string "if available" against MONDO:0009857, not a curation-relevant error, and the two unresolvable prefixes were Orphanet/ORPHA with no configured resolver. just preflight-dr returned SKIP because MONDO records no RO:0004003 causal gene for MONDO:0009857, so disease identity was checked manually instead: the report's OMIM 261550 matches MONDO's OMIM xref and its top genes are AMH and AMHR2, which is the correct disease. The report supplied the causal-chain ordering and three of the seventeen references; the remainder were found by direct PubMed E-utilities searches for the mechanism, surgical-management, malignancy and mouse-genetics literature. A GeneReviews search (term=persistent Mullerian duct syndrome GeneReviews[All Fields]) returned zero results, so no GeneReviews baseline exists for this disease. Evidence discipline. Every snippet was copied from a locally cached record and verified; nothing was reconstructed from memory. Four initial snippets failed on bracketed-citation stripping and were shortened to bracket-free spans rather than repaired by fuzzy matching. Two snippets reproduce source typographical errors verbatim ("transvers ectopia" in PMID:33532339, "the tests" for "the testes" in PMID:9187705) and say so in their explanations. directness was left unset throughout because it was not assessed. No entry uses REFUTE or NO_EVIDENCE; 5 items are MODEL_ORGANISM (mouse Amhr2-null and conditional Bmpr1a knockout) and the rest HUMAN_CLINICAL. Deliberate omissions. No conforms_to: kb/modules/ was listed and searched and no module covers loss of a TGF-beta family ligand-receptor pair (aortopathy_tgfbeta_dysregulation concerns excess TGF-beta signalling, the serial-homology modules concern repeated developmental elements); the reason is recorded in the entry notes. No datasets: block, because no disease-relevant expression dataset was identified and a gene-only GEO hit would be Named Entity Confusion. No separate Fallopian-tube phenotype, because HPO has no term for their presence in a 46,XY individual and the available fallopian-tube terms all code morphological abnormality; the tubes are curated inside the uterus phenotype. The "Normal Male External Genitalia" phenotype is deliberately left unbound for the same class of reason: HPO codes abnormal findings and this phenotype is defined by the absence of one. No ORPHA evidence, because ORPHA:2856 is not among the 349 ORPHA records committed to references_cache/ and rebuilding it needs the gitignored Orphadata bulk XML. Validation. just validate-disorders passed: schema clean, term validation passed, 90/90 snippets verified against cached references. Also run and passed on this file: validate-terms, check-entity-refs, check-causal-targets (0 prefixed, 0 dangling, 0 self), check-duplicate-keys, check-enum-values, check-qualifier-terms-online (0 qualifier terms in this entry), check-snippet-grading, check-title-snippets, check-snippet-length, check-folded-hyphens, check-reference-titles, check-environmental-evidence. just compliance reports 97.4 percent weighted compliance. normalize-cache was run; the cache diff is 14 added rows, all introduced by this entry.

Falcon ▸

Persistent Müllerian Duct Syndrome (PMDS): Disease-Characteristics Research Report

Edison Scientific Literature 13 citations 2026-09-05T19:58:38.098076

Persistent Müllerian Duct Syndrome (PMDS): Disease-Characteristics Research Report

Scope and evidence date. This report synthesizes literature retrieved through December 2024. PMDS is exceptionally rare; consequently, most evidence consists of referral cohorts, retrospective surgical series, case reports, and animal models rather than population studies or controlled trials. Percentages from the 157-case expert series are particularly vulnerable to referral and survivorship bias and should not be interpreted as population risks.

Executive summary

Persistent Müllerian duct syndrome is a congenital, usually autosomal-recessive 46,XY difference/disorder of sex development in which Müllerian derivatives—uterus, fallopian tubes, and upper vagina—persist despite otherwise normal male virilization. Biallelic loss-of-function variants in AMH or AMHR2 explain approximately 86–88% of molecularly investigated cases. Testosterone-dependent differentiation remains intact, explaining the normal male external genitalia and Wolffian derivatives. Clinical recognition usually follows surgery or imaging for cryptorchidism, inguinal hernia, transverse testicular ectopia, or infertility. Management centers on early localization and preservation of viable testes, protection of the vasa deferentia and testicular vessels, selective removal or surveillance of Müllerian remnants, fertility counseling, and tumor surveillance. There is no pharmacological or prenatal treatment capable of reversing an established embryonic developmental anomaly. (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13, mullen2019amhandamhr2 pages 1-2)

The following matrix summarizes the most actionable evidence.

Domain	Best-supported finding	Quantitative detail	Evidence type/source/date	Ontology-ready annotation
Definition / identifiers	PMDS is a congenital disorder of sex development in otherwise normally virilized 46,XY males, characterized by persistence of Müllerian derivatives such as the uterus, fallopian tubes, and upper vagina.	MONDO:0009857; Orphanet:2856	Aggregated disease-target resource and 2024 human review/case report (OpenTargets Search: Persistent Mullerian duct syndrome-AMH,AMHR2, cima2024persistentmüllerianduct pages 12-13)	MONDO:0009857; 46,XY DSD; persistent Müllerian derivatives
Causal genes	Biallelic loss-of-function variants in AMH cause deficient hormone activity (type 1); biallelic AMHR2 variants cause receptor resistance (type 2).	Approximately 88% of cases have homozygous or compound-heterozygous variants in these genes; one 157-case review found AMH variants in 40.4%, AMHR2 variants in 45.7%, and neither in 13.9%.	Human cohort/reviews, 2017–2024 (OpenTargets Search: Persistent Mullerian duct syndrome-AMH,AMHR2, liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13)	Genes: AMH, AMHR2; mechanism: germline loss of function; inheritance: autosomal recessive
Pathogenic variants	Variant classes include missense, nonsense, frameshift, splice, insertion/deletion, and AMHR2 microdeletions. A recurrent 27-bp AMHR2 kinase-domain deletion is enriched in patients of Northern European origin.	Recurrent deletion reported in 30 patients; 2024 AMHR2 c.1046T>C (p.Ile349Thr) had gnomAD frequency 0.00001591 and no homozygotes.	Human molecular cohorts/reviews and 2024 case report (cima2024persistentmüllerianduct pages 17-19, cima2024persistentmüllerianduct pages 7-10)	Sequence variants in AMH/AMHR2; germline; pathogenic/likely pathogenic/VUS classification per ACMG/AMP
Core phenotypes	Principal presentations are bilateral cryptorchidism, unilateral cryptorchidism with contralateral hernia containing Müllerian structures, and transverse testicular ectopia; external virilization is usually normal.	Bilateral intra-abdominal testes approximately 60–70%; hernia uteri inguinalis approximately 20–30%; transverse testicular ectopia approximately 10% in one review. A 2024 review grouped approximately 80% as the bilateral intra-abdominal “female form” and 20% as male forms.	Human case-series/reviews, 2017–2024 (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13)	Cryptorchidism; inguinal hernia; transverse testicular ectopia; uterus/fallopian-tube/upper-vaginal remnants; normal male external genitalia
Diagnosis	Suspect PMDS in bilateral cryptorchidism, transverse testicular ectopia, or an inguinal hernia containing uterus-like tissue. Evaluation combines examination, ultrasonography/MRI, 46,XY karyotype, serum AMH, laparoscopy/pathology, and AMH/AMHR2 sequencing with copy-number analysis when needed.	In a 2022 study, 3 of 11 unrelated cryptorchidism patients had biallelic AMH/AMHR2 variants. MRI demonstrated Müllerian remnants in all three.	Human molecular case series, January 2022 (liu2022identificationofamh pages 6-8, liu2022identificationofamh pages 2-5)	Diagnostic procedures: pelvic ultrasound, pelvic MRI, laparoscopy, karyotype, serum AMH, germline sequencing, CNV analysis, histopathology
Biomarkers	Very low or undetectable AMH supports AMH deficiency; normal or elevated AMH supports AMHR2 resistance, but age- and assay-specific interpretation is essential. Testosterone is generally preserved because Leydig-cell androgen production is not the primary defect.	Example AMH values in a 2022 series: 0.06, 3.21, and 7.72 ng/mL; the 2024 AMHR2 p.Ile349Thr case had age-appropriate AMH.	Human case series/case report, 2022 and 2024 (liu2022identificationofamh pages 2-5, cima2024persistentmüllerianduct pages 7-10)	Biomarkers: anti-Müllerian hormone, testosterone, inhibin B, LH, FSH; genotype–biomarker correlation
Malignancy / fertility	Cancer risk is driven mainly by undescended testes; malignant transformation of Müllerian remnants is reported but less frequent. Fertility is uncommon but possible if at least one testis is scrotal and its excretory ducts remain intact.	Testicular malignant degeneration was reported in 33% of adults in a selected 157-case experience; other literature estimates range from 3.1–8.4% to 5–18%. Approximately 19% reportedly fathered a child naturally.	Human referral cohort and literature reviews, 2017–2022 (cima2024persistentmüllerianduct pages 17-19, liu2022identificationofamh pages 6-8, krzeminska2024persistentmullerianduct pages 1-3, mullen2019amhandamhr2 pages 1-2)	Complications: testicular neoplasm, Müllerian-remnant neoplasm, azoospermia, oligospermia, male infertility
Management	Management is individualized: early orchiopexy when feasible, careful laparoscopic assessment, and selective subtotal/complete resection or retention of Müllerian remnants. Preservation of the vas deferens and testicular blood supply takes priority; retained remnants require surveillance.	In a 12-patient Chinese series, 8 underwent orchiopexy with uterine preservation; 3 later developed remnant cysts. Three underwent subtotal hysterectomy; one sustained vas deferens injury and one postoperative hemorrhage.	Human surgical cohort, 2022 (cima2024persistentmüllerianduct pages 16-17)	Interventions: orchiopexy, laparoscopy, hysterectomy/remnant excision, orchidectomy when indicated, fertility preservation, imaging surveillance
2024 advances	A previously unreported homozygous AMHR2 kinase-domain variant was associated with PMDS and supernumerary testes. Biochemical research also mapped AMH residues involved in type-I and type-II receptor interactions and improved precursor processing, refining understanding of receptor-complex assembly.	AMHR2 NM_020547.3:c.1046T>C (p.Ile349Thr), classified likely pathogenic; engineered AMH variants increased potency approximately 5- to 10-fold in vitro.	Human case report/review and experimental protein study, November–December 2024 (cima2024persistentmüllerianduct pages 7-10)	AMHR2 protein-kinase domain; AMH processing; ligand–receptor binding; TGF-β/BMP-family signaling
Mouse model	Homozygous Amh- or Amhr2-null male mice retain uterus, oviducts, and partial vagina despite normal testes and Wolffian derivatives, recapitulating the core human developmental lesion. Progressive seminiferous epithelial atrophy models downstream subfertility.	Amhr2-null males sired offspring at less than a 50% rate; focal tubular atrophy appeared by 2 months and markedly impaired spermatogenesis by 9 months.	Targeted knockout model/review, 2019 (mullen2019amhandamhr2 pages 4-5)	Model: Amh knockout, Amhr2 knockout; phenotypes: persistent Müllerian structures, testicular atrophy, reduced male fertility
Canine natural disease	Miniature Schnauzers have sex-limited autosomal-recessive PMDS caused by AMHR2 c.241C>T (p.Arg81*); affected XY dogs retain oviducts, uterus, cervix, and cranial vagina and may have cryptorchidism.	Among 216 North American Miniature Schnauzers, mutant-allele frequency was 0.16 and carrier frequency 0.27; approximately 50% of affected dogs had unilateral or bilateral cryptorchidism.	Natural veterinary cohort and comparative review, 2018–2019 (mullen2019amhandamhr2 pages 4-5, smit2018prevalenceofthe pages 1-2)	Species: dog; breed: Miniature Schnauzer; gene: AMHR2; variant: c.241C>T (p.Arg81*); autosomal recessive, sex limited
Canine 2024 genomics	Recent comparative analysis identified technical blind spots in canine PMDS sequencing: GC-rich repetitive AMH exon 5 has poor coverage, and AMHR2 annotation differs among canine genome assemblies. Targeted resequencing may resolve genetically unexplained cases in other breeds.	CanFam3.1 represented 11 AMHR2 coding exons with complete deep coverage; ROS_Cfam_1.0 represented only 8.	Computational genomics preprint, posted December 4, 2024 (krzeminska2024persistentmullerianduct pages 3-7, krzeminska2024persistentmullerianduct pages 7-9, krzeminska2024persistentmullerianduct pages 12-17)	Comparative genomics; AMH exon 5; AMHR2 structural annotation; targeted resequencing

Table: Concise evidence matrix covering PMDS definition, genetics, clinical features, diagnosis, outcomes, management, recent advances, and comparative models. Quantitative estimates are tied to their underlying evidence type and should be interpreted cautiously because most human data derive from rare-disease referral cohorts and case series.

1. Disease information

Definition and classification

PMDS is a Mendelian congenital 46,XY DSD characterized by persistent Müllerian structures in an otherwise normally virilized male. It is not synonymous with ambiguous genitalia: Leydig-cell testosterone production and androgen response are ordinarily intact. One recent abstract defines it as “a rare autosomal recessive disorder of sexual development in males, defined by the presence of Müllerian remnants with otherwise normal sexual differentiation.” (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13)

Identifiers and synonyms

MONDO: MONDO:0009857.
Orphanet: ORPHA:2856.
OMIM: commonly represented as PMDS type 1/AMH-related disease (OMIM 261550) and PMDS type 2/AMHR2-related disease (OMIM 600956); these identifiers should be checked against the current OMIM release before automated ingestion.
MeSH: no uniquely granular PMDS descriptor was established in the retrieved evidence; indexing commonly falls under disorders of sex development, cryptorchidism, and Müllerian ducts.
ICD-10/ICD-11: no PMDS-specific billable code was verified. Coding generally uses congenital malformations/differences of genital development plus cryptorchidism or hernia codes; local coding rules should be applied.
Synonyms: persistent Müllerian duct syndrome; Müllerian duct persistence syndrome; PMDS; persistent Müllerian derivatives; AMH deficiency/PMDS type 1; AMH-receptor resistance or AMHR2 deficiency/PMDS type 2; historically, hernia uteri inguinalis for one presentation.

OpenTargets independently links MONDO:0009857 and ORPHA:2856 to AMH and AMHR2, with supporting literature including PMIDs 28528332, 8872466, 8162013, and 23295284. (OpenTargets Search: Persistent Mullerian duct syndrome-AMH,AMHR2)

Data provenance: these are aggregated disease-level findings derived from curated resources and published cases/cohorts, not individual EHR data. The 2022 and 2024 clinical publications contain patient-level observations, but this report does not reproduce identifiable patient records.

2. Etiology, risk, protective, and environmental factors

Primary cause

The initiating cause is defective fetal AMH signaling:

Type 1 PMDS: biallelic pathogenic AMH variants cause absent, reduced, improperly processed, or biologically inactive ligand.
Type 2 PMDS: biallelic pathogenic AMHR2 variants cause receptor deficiency or resistance despite normal or elevated circulating AMH.
Genetically unresolved PMDS: approximately 12–14% of historical cases lacked detectable AMH/AMHR2 variants. Rare truncating PPP1R12A variants have subsequently implicated myosin-phosphatase/cytoskeletal regulation in Müllerian regression, but this is not yet as firmly established as AMH/AMHR2 disease. (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13, cima2024persistentmüllerianduct pages 17-19)

Risk factors

Genetic: two pathogenic alleles in AMH or AMHR2; parental consanguinity increases the probability of homozygosity. A recurrent 27-bp AMHR2 kinase-domain deletion was reported in 30 patients, mainly of Northern European ancestry, consistent with a founder-enriched allele. (cima2024persistentmüllerianduct pages 17-19)
Family history: affected brothers and carrier parents are expected under autosomal-recessive inheritance. Females carrying biallelic defects do not develop the male PMDS anatomy because Müllerian structures are normally retained in females.
Sex/chromosomal context: the defining phenotype occurs in individuals with testes, usually 46,XY, because failure is specifically failure of male fetal Müllerian regression.

No reproducible environmental, infectious, occupational, dietary, smoking, alcohol, age-related, or lifestyle cause has been demonstrated. No protective genetic allele, diet, medication, or exposure is known. PMDS is established during a critical fetal developmental window; postnatal lifestyle cannot prevent it. Gene–environment interactions, GWAS susceptibility loci, and polygenic risk scores have not been established.

3. Phenotypes

Phenotype	Characteristics and frequency	Suggested HPO term
Persistent uterus/tubes/upper vagina	Congenital and lifelong unless resected; often asymptomatic and discovered intraoperatively	Persistent Müllerian duct structures (use current HPO label/ID); abnormality of internal genitalia
Cryptorchidism	Most common presentation; bilateral intra-abdominal testes reported in approximately 60–70%; 2024 review’s “female form” ≈80%	HP:0000028 Cryptorchidism; bilateral cryptorchidism
Inguinal hernia/hernia uteri inguinalis	Uterus/tube and sometimes testis in a hernia; approximately 20–30% in one synthesis	HP:0000023 Inguinal hernia
Transverse testicular ectopia	Both testes migrate toward one hemiscrotum/inguinal canal; estimates vary around 10%, or higher in selected mutation-positive series	Testicular ectopia; transverse testicular ectopia
Male infertility	Usually recognized in adulthood; azoospermia, severe oligospermia, duct injury/obstruction, cryptorchid testicular damage	HP:0003251 Male infertility; HP:0000027 Azoospermia; oligozoospermia
Abnormal vas/excretory ducts	Frequent; vas may run tightly along uterus/tubes, creating surgical risk	Abnormal vas deferens morphology; obstructive azoospermia
Testicular hypoplasia/atrophy	Variable, worsens with prolonged ectopia; 2024 case had hypoplastic testes and absent spermatogenesis	HP:0008734 Decreased testicular size; testicular atrophy
Müllerian-remnant cysts	May arise after preservation; 3/8 patients after uterine preservation in one surgical cohort	Müllerian duct cyst
Neoplasia	Predominantly undescended-testis germ-cell tumors; rarer Müllerian-derived carcinomas/sarcomas	Testicular neoplasm; neoplasm of uterus

The three canonical anatomical presentations are bilateral cryptorchidism, unilateral cryptorchidism with contralateral hernia, and transverse testicular ectopia. Reported proportions differ because categories, referral patterns, and mutation ascertainment differ. (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 12-13, mullen2019amhandamhr2 pages 1-2)

Onset and course: the lesion is congenital, but clinical detection ranges from infancy during hernia/cryptorchidism surgery to adulthood during infertility or hematospermia evaluation. Müllerian persistence itself is stable; testicular degeneration, infertility, remnant cysts, and cancer risk are progressive secondary consequences. No behavioral or neuropsychiatric phenotype is established as part of classical biallelic PMDS.

Quality of life: no PMDS-specific EQ-5D, SF-36, PROMIS, or validated patient-reported outcome study was found. Likely burdens include repeated operations, infertility, cancer anxiety, surveillance, and possible psychosocial effects of a DSD diagnosis. These should not be converted into quantitative QOL estimates without direct data.

4. Genetic and molecular information

Causal genes and proteins

AMH (HGNC symbol AMH; Ensembl ENSG00000104899): TGF-β-superfamily ligand produced by fetal Sertoli cells. Pathogenic mechanism is predominantly germline loss of function.
AMHR2 (Ensembl ENSG00000135409): ligand-specific transmembrane serine/threonine kinase receptor. Pathogenic mechanisms include impaired expression, trafficking, ligand binding, kinase signaling, or receptor stability. (OpenTargets Search: Persistent Mullerian duct syndrome-AMH,AMHR2, cima2024persistentmüllerianduct pages 17-19)

A 157-case synthesis found AMH variants in 40.4%, AMHR2 variants in 45.7%, and neither in 13.9%. By 2017, 80 families carrying 64 AMH mutations and 75 families carrying 58 AMHR2 alleles had been reported. Variant classes include missense, nonsense, frameshift, splice-site, insertion/deletion, in-frame deletion, and exon-level microdeletion. (liu2022identificationofamh pages 5-6, cima2024persistentmüllerianduct pages 17-19)

Illustrative variants

AMH NM_000479:c.321_324del, p.Gln109LeufsTer29: homozygous frameshift, predicted loss of function; reported as likely pathogenic.
AMHR2 c.494_502del, p.Ile165_Ala168delinsThr; p.Glu390Lys; p.Met439Val, and a splice-region variant were found in adult infertility cases; classifications ranged from pathogenic/likely pathogenic to VUS, emphasizing the need for variant-specific ACMG assessment. (liu2022identificationofamh pages 5-6)
AMHR2 NM_020547.3:c.1046T>C, p.Ile349Thr: 2024 homozygous likely-pathogenic kinase-domain variant; gnomAD frequency 0.00001591, with no homozygotes. The associated phenotype included PMDS and supernumerary testes. (cima2024persistentmüllerianduct pages 7-10)
Recurrent AMHR2 27-bp kinase-domain deletion: reported in 30 patients, mainly Northern European. (cima2024persistentmüllerianduct pages 17-19)

Variants are constitutional/germline, not somatic drivers. Individual allele frequencies must be retrieved from the current gnomAD release and transcript-matched; most pathogenic alleles are absent or extremely rare. No validated modifier gene, protective allele, anticipation, or recurrent germline mosaicism pattern is established. No disease-defining methylation, histone, chromatin, metabolomic, proteomic, lipidomic, or single-cell signature has been validated.

5. Environmental information

Environmental toxins, radiation, pollution, medications, maternal infection, diet, exercise, smoking, and alcohol have not been established as causes or modifiers. PMDS is not infectious and has no zoonotic transmission. Environmental and lifestyle fields should therefore be recorded as not established/not applicable, rather than “negative exposure.”

6. Mechanism and pathophysiology

Ordered causal chain

Biallelic AMH loss-of-function or AMHR2 loss-of-function/resistance leads to insufficient AMH signaling during the male fetal Müllerian-regression window.
Insufficient ligand–receptor signaling leads to failure to assemble/activate the AMHR2–type-I BMP receptor complex in Müllerian-duct mesenchyme; ACVR1 and BMPR1A are implicated type-I receptors. (krzeminska2024persistentmullerianduct pages 1-3, mullen2019amhandamhr2 pages 1-2)
Reduced receptor serine/threonine-kinase activity leads to deficient downstream SMAD-mediated transcription and mesenchymal remodeling; the exact human cell-death/remodeling sequence is substantially inferred from developmental models rather than directly demonstrated in affected fetuses.
Failure of epithelial–mesenchymal regression leads to persistence of uterus, fallopian tubes, and upper vagina.
Preserved fetal Leydig-cell testosterone leads to normal Wolffian derivatives, male external genitalia, and usual pubertal virilization, creating the characteristic discordance between external and internal anatomy. (cima2024persistentmüllerianduct pages 12-13)
Persistent Müllerian structures and abnormal genito-inguinal ligament/gubernacular shortening lead to mechanically restricted testicular descent, producing bilateral cryptorchidism, hernia uteri inguinalis, or transverse ectopia. (cima2024persistentmüllerianduct pages 12-13)
Chronic testicular malposition plus ductal distortion and surgical vulnerability leads to impaired spermatogenesis, obstruction, azoospermia/oligospermia, and infertility.
Cryptorchid testicular tissue leads to increased germ-cell tumor risk; retained Müllerian epithelium can independently lead, much less often, to Müllerian-derived malignancy. (cima2024persistentmüllerianduct pages 17-19, liu2022identificationofamh pages 6-8, mullen2019amhandamhr2 pages 1-2)

Upstream: ligand production/processing, AMHR2 binding, receptor trafficking and kinase activity. Downstream: SMAD transcription, Müllerian mesenchymal remodeling, gubernacular/testicular positioning, later heat-associated testicular damage and neoplasia.

Suggested GO annotations: GO:0001701 in utero embryonic development; GO:0008585 female gonad development is not appropriate for the male lesion; use Müllerian duct development/regression where available; GO:0007179 TGF-β receptor signaling pathway; GO:0060395 SMAD protein signal transduction; GO:0007283 spermatogenesis; GO:0043067 regulation of programmed cell death when supported by model-specific evidence. Cell types: Sertoli cell (CL:0000216), Müllerian-duct mesenchymal cell, Müllerian-duct epithelial cell, Leydig cell (CL:0000178), germ cell/spermatogonium. Subcellular sites: secretory pathway for AMH; plasma membrane and cytoplasmic kinase domain for AMHR2; cytosol/nucleus for SMAD transduction.

There is no established primary metabolic, immune, inflammatory, oxidative-stress, mitochondrial, lysosomal, or ion-channel mechanism. Advanced single-cell, spatial-transcriptomic, and multi-omics studies directly profiling human PMDS were not found.

7. Anatomical structures affected

Primary: Müllerian ducts and derivatives—uterus, uterine tubes, cervix/upper vagina—plus testes whose descent is mechanically disturbed. Secondary: epididymides, vasa deferentia, seminal outflow tract, gubernacula, inguinal canals, and scrotum. Müllerian remnants may be midline; testes may be bilateral intra-abdominal, unilateral, inguinal, crossed, or both on one side. (cima2024persistentmüllerianduct pages 12-13, liu2022identificationofamh pages 6-8)

Suggested UBERON mappings: Müllerian duct; uterus (UBERON:0000995); uterine tube (UBERON:0003889); vagina (UBERON:0000996); testis (UBERON:0000473); vas deferens (UBERON:0001000); epididymis (UBERON:0001301); gubernaculum; inguinal canal; scrotum. IDs should be validated against the current ontology release before ingestion.

8. Temporal development

Initiation: congenital, during fetal sex differentiation and Müllerian regression.
Early clinical stage: cryptorchidism, inguinal hernia, or ectopia in infancy/childhood.
Intermediate: repeated orchiopexy, re-ascent, remnant cysts, or progressive testicular atrophy.
Adult presentation: infertility, azoospermia/oligospermia, hematospermia, or tumor.
Course: lifelong unless remnants are removed; complications accumulate variably rather than following a standardized staging system.

The principal intervention window is early childhood, when recognition during cryptorchidism/hernia assessment can prevent repeated surgery and permit timely orchiopexy. A 2024 case underwent multiple operations before molecular recognition, illustrating the real-world cost of low awareness. (cima2024persistentmüllerianduct pages 12-13, cima2024persistentmüllerianduct pages 7-10)

9. Inheritance and population

PMDS is usually autosomal recessive and sex-limited in phenotypic expression. Penetrance of Müllerian persistence appears high for biallelic severe AMH/AMHR2 defects, whereas the position and viability of testes and fertility show variable expressivity. Anticipation is not expected. De novo variants are reported but uncommon. Consanguinity is relevant; founder enrichment exists for the recurrent AMHR2 deletion. (cima2024persistentmüllerianduct pages 12-13, cima2024persistentmüllerianduct pages 17-19)

No defensible population prevalence or annual incidence per 100,000 was identified. Statements such as “fewer than 300 cases reported” measure publication rarity, not prevalence. PMDS occurs globally; no ethnicity is intrinsically protected. The affected clinical sex ratio is effectively male because the defining internal/external discordance requires testes and male differentiation.

10. Diagnostics

Practical diagnostic pathway

Suspect PMDS in bilateral/nonpalpable cryptorchidism, both testes on one side, transverse ectopia, recurrent inguinal hernia, or an unexpected uterus/tube at surgery.
Map anatomy: high-resolution inguinoscrotal and pelvic ultrasound; pelvic MRI when anatomy is uncertain; diagnostic laparoscopy remains highly informative.
Establish sex-development context: karyotype or chromosome analysis, typically 46,XY; document external virilization and palpable gonads.
Laboratory testing: AMH, inhibin B, testosterone, LH and FSH; tumor markers AFP, β-hCG and LDH when a mass is present. Very low AMH supports AMH deficiency; normal/high AMH supports AMHR2 resistance, but normal AMH does not exclude PMDS. A 2022 series reported AMH values of 0.06, 3.21 and 7.72 ng/mL across genetically distinct cases. (liu2022identificationofamh pages 2-5)
Genetics: sequence and deletion/duplication analysis of AMH and AMHR2. A DSD/cryptorchidism panel or WES is appropriate when first-line testing is negative; ensure CNV detection because AMHR2 microdeletions can be missed. WGS may resolve regulatory/structural variants, but its incremental PMDS yield is not established.
Pathology: verify Müllerian epithelium/smooth muscle and assess testicular maturation, atrophy, germ-cell neoplasia, or malignancy.

In a molecular study, 3 of 11 unrelated cryptorchidism patients carried biallelic AMH/AMHR2 variants, and MRI identified Müllerian remnants in all three—supporting genetics and MRI in selected cryptorchidism rather than universal screening. (liu2022identificationofamh pages 6-8, liu2022identificationofamh pages 2-5)

Not routinely indicated: mitochondrial sequencing, repeat-expansion testing, FISH, metabolomics, proteomics, liquid biopsy, or epigenomic testing. CMA/karyotype is useful when syndromic features or another DSD is suspected but will not detect most single-gene PMDS.

Differential diagnosis: androgen-insensitivity syndrome, 46,XY gonadal dysgenesis, testosterone-biosynthesis defects, mixed gonadal dysgenesis, ovotesticular DSD, congenital bilateral cryptorchidism without Müllerian persistence, and nonsyndromic transverse testicular ectopia. Normal male virilization plus uterus/tubes and AMH/AMHR2 biallelic variants strongly favors PMDS. Müllerian remnants can rarely coexist with another DSD, so anatomy alone is insufficient.

Screening: no newborn population screening. Offer cascade testing to siblings and carrier testing to relatives after a molecular diagnosis.

11. Outcome and prognosis

Life expectancy is generally expected to be near normal when cryptorchidism and tumors are appropriately managed, but no 5-year, 10-year, mortality, or life-expectancy cohort was found. Morbidity is reproductive and surgical rather than multisystemic.

Fertility is uncommon but possible when at least one testis is scrotal and its ductal drainage remains intact. Approximately 19% reportedly fathered a child naturally in compiled cases. TESE/micro-TESE with ICSI may enable biological paternity; in one very small series, micro-TESE retrieved sperm in 1/2 azoospermic men. (liu2022identificationofamh pages 6-8, krzeminska2024persistentmullerianduct pages 1-3, mullen2019amhandamhr2 pages 1-2)

A selected expert series reported testicular malignant degeneration in 33% of adults, whereas other reviews gave approximately 3.1–8.4% or 5–18%. The 33% figure should not be used for individual counseling as a population estimate; ascertainment and prolonged untreated cryptorchidism likely inflate it. Müllerian-remnant malignancies—adenocarcinoma, adenosarcoma and others—are documented but rarer. (cima2024persistentmüllerianduct pages 17-19, liu2022identificationofamh pages 6-8, mullen2019amhandamhr2 pages 1-2)

Prognosis is better with early testicular descent, at least one viable scrotal testis, intact vasa, avoidance of repeated operations, and absence of malignancy. No validated prognostic biomarker or calculator exists.

12. Treatment and current implementation

There is no drug, hormone, gene therapy, RNA therapy, cell therapy, or immunotherapy that can regress established Müllerian organs postnatally. Treatment is anatomical and preventive.

Orchiopexy for viable testes, preferably early; NCIT suggestion: Orchiopexy.
Laparoscopic exploration/dissection to define shared blood supply and vas anatomy; NCIT: Laparoscopic Surgical Procedure.
Selective subtotal/complete Müllerian-remnant excision or hysterectomy when safely separable, symptomatic, cystic, or suspicious; NCIT: Hysterectomy/Surgical Resection.
Preservation with surveillance when excision threatens the vas deferens or testicular vessels.
Orchidectomy for nonviable/atrophic testis or malignancy concern; NCIT: Orchiectomy.
Fertility care: semen analysis, cryopreservation when sperm are present, TESE/micro-TESE and ICSI; NCIT: Sperm Cryopreservation, Testicular Sperm Extraction, Intracytoplasmic Sperm Injection.
Supportive care: genetic counseling, endocrine follow-up where gonadal function is compromised, tumor surveillance, and psychosocial DSD-informed care.

There is no consensus guideline on routine uterus removal. In a 12-patient Chinese series, 8 underwent orchiopexy with uterine preservation; 3 developed remnant cysts. Of 3 undergoing subtotal hysterectomy, one sustained vas injury and one postoperative hemorrhage. These observations support individualized, anatomy-preserving surgery rather than mandatory excision. (cima2024persistentmüllerianduct pages 16-17)

No PMDS-specific interventional ClinicalTrials.gov study was identified. Pharmacogenomic guidance is not applicable to the congenital lesion.

13. Prevention

Primary prevention: no lifestyle or vaccine prevention. In known families, carrier testing, genetic counseling, prenatal diagnosis, and PGT-M are technically possible after identifying familial variants; use requires nondirective counseling.
Secondary prevention: early recognition in cryptorchidism/hernia, preoperative imaging and AMH/genetic testing, and cascade testing can reduce delayed diagnosis and repeated surgery.
Tertiary prevention: timely orchiopexy, preservation of vas/vessels, fertility preservation, surveillance of testes and retained remnants, and prompt evaluation of masses, pain, bleeding, or hematospermia.

For an autosomal-recessive couple in which both partners carry the same disease-causing gene defect, each pregnancy has a 25% probability of biallelic inheritance; phenotypic consequences depend on fetal sex and gonadal development. No public-health or environmental intervention is indicated.

14. Other species and natural disease

Naturally occurring PMDS is best characterized in the domestic dog (Canis lupus familiaris, NCBI Taxon 9615), particularly Miniature Schnauzers. A sex-limited recessive AMHR2 c.241C>T, p.Arg81Ter nonsense allele prevents signaling. Among 216 North American Miniature Schnauzers, allele frequency was 0.16 and carrier frequency 0.27; approximately half of affected dogs had unilateral or bilateral cryptorchidism. Retained oviducts, uterus, cervix and cranial vagina, pyometra, infertility, and Sertoli-cell tumors have veterinary relevance. (mullen2019amhandamhr2 pages 4-5, smit2018prevalenceofthe pages 1-2)

A 2024 canine preprint found that GC-rich repetitive AMH exon 5 is poorly covered by WGS/RNA-seq and that AMHR2 annotation differs markedly among canine assemblies. It recommends targeted resequencing of unresolved cases in Yorkshire Terriers and other breeds. This is a computational/preprint result, not yet definitive evidence of new causal alleles. (krzeminska2024persistentmullerianduct pages 3-7, krzeminska2024persistentmullerianduct pages 7-9, krzeminska2024persistentmullerianduct pages 12-17)

PMDS is not transmissible or zoonotic. Veterinary prevention consists of genotyping and avoiding carrier-to-carrier matings, not infection control.

15. Model organisms

Mouse

Targeted Amh-null and Amhr2-null male mice retain a uterus, oviducts, and partial vagina despite normal testes and Wolffian structures, closely recapitulating the developmental core of human PMDS. Amhr2-null males can reproduce, but at less than a 50% rate and with smaller litters; focal seminiferous epithelial atrophy appears by 2 months and markedly reduces spermatogenesis by 9 months. These models support studies of ligand/receptor signaling, Müllerian regression, testicular descent, duct anatomy, and fertility. (mullen2019amhandamhr2 pages 4-5)

Limitations: mouse fertility is better preserved than in many clinical cases; surgical history and prolonged human cryptorchidism are not reproduced; species-specific reproductive anatomy differs; and constitutive knockouts do not model every human missense allele’s trafficking or residual function.

Other experimental systems

Cell-based receptor assays can distinguish deficient AMH processing, receptor binding, trafficking, and kinase signaling. A 2024 biochemical study improved AMH precursor cleavage to over 90% and engineered variants with approximately 5- to 10-fold greater in-vitro potency; this clarifies receptor-complex assembly but is not a PMDS therapy. No validated PMDS patient-derived organoid, iPSC, CRISPR-screen, spatial-transcriptomic, or humanized model was identified.

Recent developments and expert interpretation

Expanded genotype/phenotype spectrum: the 2024 AMHR2 p.Ile349Thr report links a very rare kinase-domain variant to PMDS with supernumerary testes and demonstrates why normal serum AMH should trigger receptor-focused analysis. Its abstract emphasizes that “a high degree of suspicion and awareness is needed … to avoid iterative surgery.” (cima2024persistentmüllerianduct pages 7-10)
Beyond AMH/AMHR2: genetically unresolved cases and reported PPP1R12A truncations suggest additional cytoskeletal/remodeling pathways, but evidence remains limited and should not displace AMH/AMHR2 first-line testing. (cima2024persistentmüllerianduct pages 12-13, cima2024persistentmüllerianduct pages 17-19)
Precision surgery rather than uniform hysterectomy: experts prioritize descended viable testes and intact vasa over complete Müllerian removal because remnants and male excretory ducts may share close attachments and blood supply. The small Chinese cohort quantifies both preservation-related cysts and excision-related injuries. (cima2024persistentmüllerianduct pages 16-17)
Sequencing blind spots matter: AMHR2 CNVs and GC-rich AMH regions can evade routine analysis; negative panel/WES results do not exclude pathway disease. Canine comparative genomics reinforces this methodological concern. (krzeminska2024persistentmullerianduct pages 3-7, krzeminska2024persistentmullerianduct pages 7-9, krzeminska2024persistentmullerianduct pages 12-17)

Evidence gaps and knowledge-base cautions

No reliable population incidence, prevalence, carrier frequency, survival curve, standardized QOL result, evidence-based surveillance interval, prospective surgical comparison, or interventional trial exists. Phenotype and malignancy percentages derive from heterogeneous published/referral cases. Ontology IDs—especially granular HPO, UBERON, CL, NCIT and legacy OMIM mappings—should be programmatically validated against current releases before ingestion. Exact abstract quotations are necessarily sparse because several mechanistic sources were reviews or full-text excerpts rather than accessible PubMed abstracts.

References

(liu2022identificationofamh pages 5-6): Yang Liu, Sida Wang, Ruzhu Lan, and Jun Yang. Identification of amh and amhr2 variants led to the diagnosis of persistent müllerian duct syndrome in three cases. Jan 2022. URL: https://doi.org/10.3390/genes13010159, doi:10.3390/genes13010159. This article has 9 citations.
(cima2024persistentmüllerianduct pages 12-13): Luminita Nicoleta Cima, Iustina Grosu, Isabela Magdalena Draghici, Augustina Cornelia Enculescu, Adela Chirita-Emandi, Nicoleta Andreescu, Maria Puiu, Carmen Gabriela Barbu, and Simona Fica. Persistent müllerian duct syndrome with supernumerary testicles due to a novel homozygous variant in the amhr2 gene and literature review. Diagnostics, 14:2621, Nov 2024. URL: https://doi.org/10.3390/diagnostics14232621, doi:10.3390/diagnostics14232621. This article has 3 citations.
(mullen2019amhandamhr2 pages 1-2): Rachel D. Mullen, Alejandra E. Ontiveros, Malcolm M. Moses, and Richard R. Behringer. Amh and amhr2 mutations: a spectrum of reproductive phenotypes across vertebrate species. Developmental biology, 455:1-9, Nov 2019. URL: https://doi.org/10.1016/j.ydbio.2019.07.006, doi:10.1016/j.ydbio.2019.07.006. This article has 66 citations and is from a peer-reviewed journal.
(OpenTargets Search: Persistent Mullerian duct syndrome-AMH,AMHR2): Open Targets Query (Persistent Mullerian duct syndrome-AMH,AMHR2, 4 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(cima2024persistentmüllerianduct pages 17-19): Luminita Nicoleta Cima, Iustina Grosu, Isabela Magdalena Draghici, Augustina Cornelia Enculescu, Adela Chirita-Emandi, Nicoleta Andreescu, Maria Puiu, Carmen Gabriela Barbu, and Simona Fica. Persistent müllerian duct syndrome with supernumerary testicles due to a novel homozygous variant in the amhr2 gene and literature review. Diagnostics, 14:2621, Nov 2024. URL: https://doi.org/10.3390/diagnostics14232621, doi:10.3390/diagnostics14232621. This article has 3 citations.
(cima2024persistentmüllerianduct pages 7-10): Luminita Nicoleta Cima, Iustina Grosu, Isabela Magdalena Draghici, Augustina Cornelia Enculescu, Adela Chirita-Emandi, Nicoleta Andreescu, Maria Puiu, Carmen Gabriela Barbu, and Simona Fica. Persistent müllerian duct syndrome with supernumerary testicles due to a novel homozygous variant in the amhr2 gene and literature review. Diagnostics, 14:2621, Nov 2024. URL: https://doi.org/10.3390/diagnostics14232621, doi:10.3390/diagnostics14232621. This article has 3 citations.
(liu2022identificationofamh pages 6-8): Yang Liu, Sida Wang, Ruzhu Lan, and Jun Yang. Identification of amh and amhr2 variants led to the diagnosis of persistent müllerian duct syndrome in three cases. Jan 2022. URL: https://doi.org/10.3390/genes13010159, doi:10.3390/genes13010159. This article has 9 citations.
(liu2022identificationofamh pages 2-5): Yang Liu, Sida Wang, Ruzhu Lan, and Jun Yang. Identification of amh and amhr2 variants led to the diagnosis of persistent müllerian duct syndrome in three cases. Jan 2022. URL: https://doi.org/10.3390/genes13010159, doi:10.3390/genes13010159. This article has 9 citations.
(krzeminska2024persistentmullerianduct pages 1-3): Paulina Krzeminska. Persistent mullerian duct syndrome in dogs – a new insight into organization of amh and amhr2 genes. bioRxiv, Dec 2024. URL: https://doi.org/10.1101/2024.11.28.625841, doi:10.1101/2024.11.28.625841. This article has 1 citations.
(cima2024persistentmüllerianduct pages 16-17): Luminita Nicoleta Cima, Iustina Grosu, Isabela Magdalena Draghici, Augustina Cornelia Enculescu, Adela Chirita-Emandi, Nicoleta Andreescu, Maria Puiu, Carmen Gabriela Barbu, and Simona Fica. Persistent müllerian duct syndrome with supernumerary testicles due to a novel homozygous variant in the amhr2 gene and literature review. Diagnostics, 14:2621, Nov 2024. URL: https://doi.org/10.3390/diagnostics14232621, doi:10.3390/diagnostics14232621. This article has 3 citations.
(mullen2019amhandamhr2 pages 4-5): Rachel D. Mullen, Alejandra E. Ontiveros, Malcolm M. Moses, and Richard R. Behringer. Amh and amhr2 mutations: a spectrum of reproductive phenotypes across vertebrate species. Developmental biology, 455:1-9, Nov 2019. URL: https://doi.org/10.1016/j.ydbio.2019.07.006, doi:10.1016/j.ydbio.2019.07.006. This article has 66 citations and is from a peer-reviewed journal.
(smit2018prevalenceofthe pages 1-2): M. M. Smit, K. J. Ekenstedt, K. Minor, C. Lim, P. Leegwater, and E. Furrow. Prevalence of the amhr2 mutation in miniature schnauzers and genetic investigation of a belgian malinois with persistent müllerian duct syndrome. Reproduction in Domestic Animals, 53:371–376, Apr 2018. URL: https://doi.org/10.1111/rda.13116, doi:10.1111/rda.13116. This article has 23 citations and is from a peer-reviewed journal.
(krzeminska2024persistentmullerianduct pages 3-7): Paulina Krzeminska. Persistent mullerian duct syndrome in dogs – a new insight into organization of amh and amhr2 genes. bioRxiv, Dec 2024. URL: https://doi.org/10.1101/2024.11.28.625841, doi:10.1101/2024.11.28.625841. This article has 1 citations.
(krzeminska2024persistentmullerianduct pages 7-9): Paulina Krzeminska. Persistent mullerian duct syndrome in dogs – a new insight into organization of amh and amhr2 genes. bioRxiv, Dec 2024. URL: https://doi.org/10.1101/2024.11.28.625841, doi:10.1101/2024.11.28.625841. This article has 1 citations.
(krzeminska2024persistentmullerianduct pages 12-17): Paulina Krzeminska. Persistent mullerian duct syndrome in dogs – a new insight into organization of amh and amhr2 genes. bioRxiv, Dec 2024. URL: https://doi.org/10.1101/2024.11.28.625841, doi:10.1101/2024.11.28.625841. This article has 1 citations.

Artifacts

Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome	Count
References checked	5
Resolved	5
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	5
On topic	4
Off topic	0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome	Count
Terms checked	22
Resolved	20
Unresolved (possible confabulation)	0
Obsolete	0
Unverifiable	2
Terms whose name was checked	1
Terms named correctly	0
Terms named as a different term	1

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

MONDO:0009857 (5 mentions) - the report calls it "if available"; MONDO calls it persistent Mullerian duct syndrome

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: Orphanet, ORPHA.

Ask OpenScientist

OpenScientist Report

Mappings

Inheritance

Subtypes

Discussions and Knowledge Gaps

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

Biochemical Markers

Diagnosis

Prevalence

Animal Models

Source YAML

References & Deep Research

Deep Research

Persistent Müllerian Duct Syndrome (PMDS): Disease-Characteristics Research Report

Executive summary

1. Disease information

Definition and classification

2. Etiology, risk, protective, and environmental factors

Primary cause

Risk factors

3. Phenotypes

4. Genetic and molecular information

Causal genes and proteins

Illustrative variants

5. Environmental information

6. Mechanism and pathophysiology

Ordered causal chain

7. Anatomical structures affected

8. Temporal development

9. Inheritance and population

10. Diagnostics

Practical diagnostic pathway

11. Outcome and prognosis

12. Treatment and current implementation

13. Prevention

14. Other species and natural disease

15. Model organisms

Mouse

Other experimental systems

Recent developments and expert interpretation

Evidence gaps and knowledge-base cautions

Artifacts

Reference Validation

Term Validation

Terms the report names something else

Prefixes with no resolver