Miniature Schnauzer — Persistent Müllerian Duct Syndrome (hereditary; OMIA-verified breed predisposition)

--- license: permission_granted topic_id: companion_breed_health_miniature_schnauzer_persistent_m_llerian_duct_syndrome_dog category: companion-breed-health title: "Miniature Schnauzer — Persistent Müllerian Duct Syndrome (hereditary; OMIA-verified breed predisposition)" lang: en source: "OMIA (Online Mendelian Inheritance in Animals, University of Sydney) breed-specific hereditary-disorder record, saved verbatim to source_file; C1 substring-verified. Pulled 2026-08-02 from local OMIA database dump." source_file: pdf-raw/breed-health/miniature_schnauzer_persistent_m_llerian_duct_syndrome_5607.txt date_parsed: 2026-08-02 tokens_estimated: 1045 verification: method: substring_match claims: 10 passed: 10 date: 2026-08-02 recovered: false path: companion-breed-health/companion_breed_health_miniature_schnauzer_persistent_m_llerian_duct_syndrome_dog/01_companion_breed_health_miniature_schnauzer_persistent_m_llerian_duct_syndrome_dog.md source_document: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" citation: authority: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" title: "Miniature Schnauzer — Persistent Müllerian Duct Syndrome (hereditary; OMIA-verified breed predisposition)" url: "https://omia.org/OMIA002775/9615/" retrieved: "2026-08-02" ref: "OMIA breed-specific hereditary-disorder records (omia.org), derived from local OMIA database dump; dataset: https://doi.org/10.25910/2AMR-PV70" doc_type: "academic animal-genetics database (breed-specific disorder entries)" needs_review: false

Miniature Schnauzer — Persistent Müllerian Duct Syndrome (hereditary; OMIA-verified breed predisposition)

Source: first-hand OMIA (University of Sydney) breed-specific hereditary-disorder record, saved verbatim to source_file; every claim below is a C1 byte-substring of it.

Claims

• Breed: Miniature Schnauzer (Dog)
• Disorder: Persistent Müllerian Duct Syndrome
• Mode of inheritance: Autosomal recessive
• Summary: Information relating to persistent Mullerian duct syndrome due to variants in the AMRH2 gene were previously listed under a href=https://omia.org/OMIA000791/9615/OMIA:000791-9615/a : Persistent Mullerian duct syndrome in Canis lupus familiaris. PMDS is a type of XY disorder of sexual development (XY DSD), characterized by the presence of Müllerian duct derivatives in otherwise normal males. The mode of inheritance for the PMDS trait in miniature schnauzers is sex-limited autosomal recessive. Affected dogs are 78,XY and have bilateral testes. Both affected and carrier males appear externally normal, although approximately 50% of affected dogs are unilaterally or bilaterally cryptorchid. Common sequelae are Sertoli cell tumors in cryptorchid PMDS males and pyometra. Treatment in affected dogs is gonadectomy and hysterectomy. Testing for the mutation prior to breeding is recommended, because affected dogs with scrotal testes are fertile and carriers have no clinical signs. Edited by Vicki N. Meyers-Wallen, VMD, PhD, Dipl. ACT, updated by Imke Tammen [28/09/2023]
• Clin feat: Homozygous affected males have normal male external genitalia, except that approximately 50% are unilaterally or bilaterally cryptorchid. PMDS males having at least one descended testicle can be fertile. Carrier males and carrier females are reproductively normal. PMDS dogs may present at any age as a dog with normal male external genitalia or a cryptorchid dog. If cryptorchid, they may present as an adult with signs of testicular tumor. As pyometra can be a sequelae, affected dogs may present with typical signs,such as polydipsia, polyuria and inappetance.
• Defect: yes
• Pathology: During development of the male reproductive tract, Müllerian inhibiting substance (MIS), also known as Anti Mullerian hormone (AMh), causes regression of Mullerian duct precursors in males. MIS binding to its type II receptor (AMhR2) in the target organs is necessary to induce regression. If MIS signaling is faulty, the Müllerian ducts fail to regress in males, causing PMDS [Wu et al., 2009]. In addition to having male internal genitalia, PMDS males have bilateral oviducts, a complete uterus , a cervix, and the cranial part of the vagina, which ends in the dorsal prostate. There is a firm attachment between each cranial tip of the uterine horn and the caudal pole of the testis, which likely hinders testicular descent [Wu et al., 2009]. Some common complications are Sertoli cell tumors in cryptorchid PMDS dogs and pyometra. Pyometra may be facilitated by the narrow connection between the cranial vagina and the prostatic urethra, which allows pathogens to ascend to the uterus, but impedes purulent drainage [Wu et al., 2009]. On histologic section, cryptorchid testes from PMDS dogs lack germ cells, though scrotal testes appear normal.
• Prevalence: Smit et al. (2018): Genomic DNA from 216 Miniature Schnauzers (including one known PMDS case) was genotyped for the AMHR2 mutation, revealing an AMHR2 mutation allele frequency of 0.16 and a carrier genotypic frequency of 0.27.
• Control: To prevent PMDS, affected dogs should not be bred and carriers should not be bred to carriers. To reduce the frequency of the mutation in the miniature schnauzer breed, carriers should be removed from the breeding population. Because affected and carrier miniature schnauzers can have normal male external genitalia, testing for the mutation prior to breeding is recommended. As carrier females have no signs and are reproductively normal, testing for the mutation prior to breeding is recommended.
• Gen test: The causative mutation of PMDS in the miniature schnauzer is a C to T transition in exon 3 of the Müllerian inhibiting substance type II receptor gene (AMHR2, Wu et al., 2009). A DNA test for this mutation can identify affected, carrier and normal miniature schnauzers (Pujar et al 2009). This is a PCR test followed by digestion of the PCR product by a restriction enzyme.

Associated gene(s)

Derived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.

• Gene: Entrez Gene ID 3484440 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene
• OMIA molecular-genetics note: Wu et al. (2009) reported that the causative mutation of PMDS in the miniature schnauzer is a C to T transition in exon 3 of the Müllerian inhibiting substance type II receptor gene (MISRII, now known as AMHR2). Smit et al. (2018): "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 [in an affected dog]"

Evidence (references)

Derived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.

• 1976. Male pseudohermaphroditism, cryptorchism, and Sertoli cell neoplasia in three miniature Schnauzers. J Am Vet Med Assoc — PubMed:PMID10267 — OMIA Phene_Article / Article
• 2009. A single base pair mutation encoding a premature stop codon in the MIS type II receptor is responsible for canine persistent Mullerian duct syndrome. J Androl — PubMed:PMID18723470 | DOI:10.2164/jandrol.108.005736 — OMIA Phene_Article / Article
• 1982. Persistent Mullerian duct syndrome in miniature schnauzers. J Am Vet Med Assoc — PubMed:PMID7141975 — OMIA Phene_Article / Article
• 2009. A molecular diagnostic test for persistent Müllerian duct syndrome in miniature schnauzer dogs. Sex Dev — PubMed:PMID20051676 | DOI:10.1159/000273264 — OMIA Phene_Article / Article
• 2009. Review and update: genomic and molecular advances in sex determination and differentiation in small animals. Reprod Domest Anim — PubMed:PMID19754534 | DOI:10.1111/j.1439-0531.2009.01433.x — OMIA Phene_Article / Article
• 2009. A case of persistent Müllerian duct syndrome with sertoli cell tumor and hydrometra in a dog. J Vet Med Sci — PubMed:PMID19346713 — OMIA Phene_Article / Article
• 2010. Persistent Mullerian duct syndrome in a Miniature Schnauzer dog with signs of feminization and a Sertoli cell tumour. Reprod Domest Anim — PubMed:PMID18954385 | DOI:10.1111/j.1439-0531.2008.01223.x — OMIA Phene_Article / Article
• 2011. Ambiguous genitalia in a fertile, unilaterally cryptorchid male miniature schnauzer dog. Vet Pathol — PubMed:PMID21248100 | DOI:10.1177/0300985810396104 — OMIA Phene_Article / Article
• 2018. Sertoli cell tumour and uterine leiomyoma in Miniature Schnauzer dogs with persistent Müllerian duct syndrome caused by mutation in the AMHR2 gene. J Comp Pathol — PubMed:PMID30173854 | DOI:10.1016/j.jcpa.2018.04.004 — OMIA Phene_Article / Article
• 2018. Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome. Reprod Domest Anim — PubMed:PMID29194807 | DOI:10.1111/rda.13116 — OMIA Phene_Article / Article
• 2019. Persistent Mullerian duct Syndrome in a Brazilian miniature schnauzer dog. An Acad Bras Cienc — PubMed:PMID31241703 | DOI:10.1590/0001-3765201920180752 — OMIA Phene_Article / Article
• 2023. Genome sequencing of 2000 canids by the Dog10K consortium advances the understanding of demography, genome function and architecture. Genome Biol — PubMed:PMID37582787 | DOI:10.1186/s13059-023-03023-7 — OMIA Phene_Article / Article

Comparative medicine (human OMIM)

Derived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.

• OMIM:261550 (type: trait) — OMIA Group_OMIM (via OMIA_ID)
• OMIM:600956 (type: gene) — OMIA Group_OMIM (via OMIA_ID)

verification_derived: method: derived_from_dataset source: "OMIA database dump (omia.xml, local); fields Gene/Variant/Article/OMIM" note: "Structured fields (gene, variant rsID/protein change, PubMed/DOI references, OMIM cross-link) extracted from OMIA dump and presented with first-hand values; not verbatim prose."