# AMH Gene: Structure, Function, and Clinical Significance


## Key Takeaways

- The AMH gene, located at 19p13.3, encodes a dimeric glycoprotein of the TGF-β superfamily crucial for male sexual differentiation (Müllerian duct regression) and female folliculogenesis. Its expression is restricted to Sertoli cells in fetal testes and granulosa cells in ovarian follicles.
- AMH signaling operates via a heteromeric receptor complex (AMHR2 and a type I receptor like ALK2/3/6), activating SMAD1/5/8 and SMAD4 for nuclear translocation and target gene regulation, with potential non-canonical MAPK/ERK and PI3K/AKT pathway involvement.
- Pathogenic mutations in AMH are implicated in Persistent Müllerian Duct Syndrome (PMDS) and Premature Ovarian Insufficiency (POI), while specific polymorphisms (e.g., rs10407022, rs10417628) are associated with Polycystic Ovary Syndrome (PCOS) and altered serum AMH levels.
- Clinically, AMH serves as a vital biomarker for ovarian reserve assessment and a diagnostic adjunct in Disorders of Sex Development (DSD), with low levels indicating diminished reserve and high levels potentially predicting OHSS risk in assisted reproduction.
- Recombinant AMH (rhAMH) is being explored as a therapeutic agent for fertility preservation by protecting primordial follicles from gonadotoxic treatments and as a potential anti-cancer agent targeting AMHR2-expressing ovarian cancers.

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## Executive Summary & Key Metadata

Anti-Müllerian hormone (AMH), also known as Müllerian inhibiting substance (MIS), is a dimeric glycoprotein belonging to the transforming growth factor-beta (TGF-β) superfamily. The AMH gene encodes a critical developmental morphogen responsible for the regression of Müllerian ducts during male embryogenesis, and serves as a central regulator of folliculogenesis and ovarian reserve in females [48, 71]. The gene is expressed in Sertoli cells of the fetal testis and in granulosa cells of pre-antral and small antral ovarian follicles [2, 78]. Beyond its canonical roles in sexual differentiation, AMH has emerged as a clinically indispensable biomarker for ovarian reserve assessment, a diagnostic adjunct in disorders of sex development (DSD), and a potential therapeutic target in oncology and reproductive medicine [34, 81].

| **Metadata Field** | **Value** |
|---|---|
| HGNC Symbol | AMH |
| UniProt Accession | P03971 |
| Representative PDB ID | 1S4Y (pro-TGF-β-like domain); 2HGR (mature domain) |
| Chromosomal Locus | 19p13.3 |
| Primary Molecular Function | TGF-β superfamily cytokine; Müllerian duct regression; ovarian follicle recruitment inhibition |
| Disease & Pathology Associations | Persistent Müllerian duct syndrome (PMDS); Premature ovarian insufficiency (POI); Polycystic ovary syndrome (PCOS); Disorders of sex development (DSD); Granulosa cell tumors |

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Chromosomal Localization and Gene Structure

The human AMH gene is located on the short arm of chromosome 19 at cytogenetic band 19p13.3. The gene spans approximately 2.8 kilobases of genomic DNA and comprises five exons separated by four introns [48]. The coding sequence is contained within a ~1.7 kb open reading frame that translates into a 560-amino-acid precursor protein. The genomic organization is highly conserved across vertebrates, with the five-exon structure maintained from teleosts to mammals, although notable exceptions exist in certain fish lineages where the gene has undergone duplication or truncation events [7, 13, 42].

The AMH locus is flanked by several genes of interest. Immediately upstream lies a bi-directional promoter shared with the SF3A2 (SAP62) gene, which encodes a splicing factor, and an expressed GNRP-like gene [54]. This arrangement imposes constraints on the promoter architecture and may contribute to tissue-specific regulation. The promoter region lacks a canonical TATA box but contains multiple GC-rich elements and binding sites for several transcription factors critical for Sertoli cell and granulosa cell expression [10, 48].

### 1.2 Promoter Architecture and Transcription Factor Binding

The AMH promoter is a paradigm for cell-type-specific transcriptional regulation. Deletion and mutagenesis studies have identified several cis-acting elements essential for high-level expression in Sertoli cells. The proximal promoter contains binding sites for steroidogenic factor 1 (SF1/NR5A1), GATA-binding factor 4 (GATA4), and SOX9, which act synergistically to drive testicular expression [23, 52]. SF1 binding at approximately -200 bp relative to the transcription start site is required for basal promoter activity, and mutations in the SF1 response element abolish expression in Sertoli cell lines [23].

The Wilms tumor suppressor gene product WT1 also binds to the AMH promoter and cooperates with SF1 to activate transcription [33]. A downstream enhancer element located in the first intron has been shown to be required for strong expression in pre-pubertal Sertoli cells, and this enhancer interacts with the proximal promoter through chromatin looping mechanisms [33, 53]. The 3' untranslated region (UTR) contains additional regulatory elements that function as enhancers or repressors depending on the cellular context [53].

In granulosa cells, the transcriptional regulation of AMH differs from that in Sertoli cells. The forkhead transcription factor FOXL2 is a key activator of AMH expression in ovarian granulosa cells, and mutations in FOXL2 that cause blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) are associated with diminished AMH expression [69]. The promoter also contains estrogen response elements (EREs), and estrogen exposure has been shown to upregulate AMH expression in granulosa cells, a finding with implications for understanding the effects of endocrine-disrupting chemicals on ovarian function [37].

### 1.3 Alternative Splicing and Isoforms

Alternative splicing of the AMH gene produces multiple mRNA isoforms, although the functional significance of these variants remains incompletely characterized. In the European sea bass (*Dicentrarchus labrax*), multiple alternatively-spliced isoforms have been identified, some of which lack exon 2 or exon 5 [42]. These isoforms are predicted to encode truncated proteins that may act as dominant-negative regulators of AMH signaling, although definitive functional studies are lacking.

In humans, several splice variants have been reported in the NCBI and Ensembl databases, but the predominant transcript encodes the full-length 560-amino-acid precursor. A naturally occurring read-through transcript that fuses AMH with the downstream gene has been described, but its biological relevance is uncertain. The presence of multiple isoforms in fish species suggests that alternative splicing may contribute to the functional diversification of AMH signaling across vertebrates [42, 92].

### 1.4 Polymorphic Variants and Population Genetics

The AMH gene harbors several common single nucleotide polymorphisms (SNPs) that have been extensively studied for their association with reproductive phenotypes. The most well-characterized coding variant is rs10407022 (Ile49Ser), located in exon 1, which has been investigated for its association with polycystic ovary syndrome (PCOS), ovarian response to stimulation, and serum AMH levels [1, 74]. The functional impact of this variant remains controversial, with some studies reporting reduced AMH bioactivity and others finding no significant effect [74].

A genome-wide association study (GWAS) in males identified common and low-frequency variants at the AMH locus that strongly predict serum AMH levels [15]. The lead variant, rs10417628, is located in the promoter region and is associated with reduced AMH expression. This variant has also been implicated in a case of a woman with classical PCOS who had undetectable serum AMH levels despite a high antral follicle count, suggesting that the variant may cause a loss of AMH immunoactivity [5].

Promoter polymorphisms, including rs10406324, have been associated with lower serum AMH levels in PCOS patients [40]. These findings underscore the importance of genetic variation at the AMH locus in modulating circulating AMH concentrations and potentially influencing reproductive outcomes.

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Primary Structure and Domain Organization

The AMH precursor protein is synthesized as a 560-amino-acid preproprotein with a molecular weight of approximately 60 kDa per monomer. The protein undergoes proteolytic processing to generate the biologically active C-terminal mature domain. The domain architecture can be divided into four distinct regions:

1. **Signal peptide (residues 1-18):** Directs the nascent polypeptide into the endoplasmic reticulum for secretion.
2. **Pro-domain (residues 19-451):** Also known as the N-terminal pro-region, this domain is required for proper folding, dimerization, and secretion of the mature protein. It contains a conserved cleavage site (RXXR motif) recognized by subtilisin-like proprotein convertases.
3. **Mature domain (residues 452-560):** The C-terminal region that constitutes the biologically active cytokine. This domain contains the conserved seven-cysteine motif characteristic of the TGF-β superfamily.
4. **Cysteine-knot motif:** The hallmark structural feature of TGF-β family members, formed by six conserved cysteine residues that create a rigid knot-like structure through disulfide bonding.

### 2.2 Three-Dimensional Structure

The three-dimensional structure of AMH has been determined by X-ray crystallography, revealing a homodimeric architecture typical of TGF-β superfamily ligands. Each monomer adopts a β-sandwich fold composed of two β-sheets, with the cysteine-knot motif at the core. The mature domain dimerizes through an intermolecular disulfide bond involving the seventh cysteine residue, which is unique to AMH among TGF-β family members.

The pro-domain forms a distinct structural unit that wraps around the mature domain, shielding the receptor-binding epitopes and maintaining the ligand in a latent state. Proteolytic cleavage at the RXXR site releases the mature dimer, which then becomes competent to bind the AMH type II receptor (AMHR2). Structural studies have revealed that the pro-domain remains non-covalently associated with the mature domain after cleavage, and this association modulates receptor binding affinity [51].

The receptor-binding interface is located on the concave surface of the mature domain dimer, involving residues from the α-helix and the pre-helix loop. Mutations in this interface, such as those identified in patients with persistent Müllerian duct syndrome, disrupt receptor binding and abolish signaling [17, 18].

### 2.3 Post-Translational Modifications

AMH undergoes several post-translational modifications that are critical for its function. N-linked glycosylation occurs at two conserved asparagine residues (Asn-319 and Asn-356) in the pro-domain. Glycosylation is required for efficient secretion and stability of the protein, and alterations in glycosylation patterns can affect AMH bioactivity [97]. The mature domain is not glycosylated, consistent with the absence of consensus N-glycosylation sites in this region.

Proteolytic processing at the RXXR motif is mediated by furin and other proprotein convertases. This cleavage occurs intracellularly in the trans-Golgi network or extracellularly at the cell surface. The efficiency of cleavage varies among tissues and developmental stages, providing a mechanism for regulating the ratio of precursor to mature AMH in the circulation [48].

### 2.4 Interactive 3D Visualizer

[Interactive 3D Protein Visualizer: Load AMH (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=P03971)

The interactive visualizer allows exploration of the AMH protein structure, including the pro-domain, mature domain, cysteine-knot motif, and receptor-binding interface. Users can rotate the structure, highlight specific residues, and visualize the dimeric assembly. The tool integrates structural data from the RCSB Protein Data Bank with UniProt annotations to provide a comprehensive view of the protein's architecture.

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 Canonical Signaling Pathway

AMH signals through a heteromeric receptor complex comprising the type II receptor AMHR2 and a type I receptor, primarily ALK2 (ACVR1), ALK3 (BMPR1A), or ALK6 (BMPR1B) [51, 59]. The signaling cascade is initiated when the mature AMH dimer binds to AMHR2, which is a constitutively active serine/threonine kinase. Ligand binding induces the recruitment and phosphorylation of a type I receptor, which in turn phosphorylates receptor-regulated SMAD proteins (R-SMADs), specifically SMAD1, SMAD5, and SMAD8/9.

The phosphorylated R-SMADs form a complex with the common mediator SMAD4 and translocate to the nucleus, where they regulate the transcription of target genes. The specificity of the transcriptional response is determined by the repertoire of transcription factors co-expressed in the target cell and the chromatin state at AMH-responsive gene loci [51].

```mermaid
sequenceDiagram
    participant AMH as "AMH Dimer"
    participant AMHR2 as "AMHR2 (Type II)"
    participant ALK as "ALK2/3/6 (Type I)"
    participant RSMAD as "R-SMAD (SMAD1/5/8)"
    participant SMAD4 as "SMAD4 (Co-SMAD)"
    participant NUC as "Nucleus"
    AMH->>AMHR2: Ligand binding
    AMHR2->>ALK: Phosphorylation of Type I receptor
    ALK->>RSMAD: Phosphorylation of R-SMAD
    RSMAD->>SMAD4: Complex formation
    SMAD4->>NUC: Nuclear translocation
    NUC->>NUC: Transcriptional regulation of target genes
```

### 3.2 Non-Canonical Signaling

Emerging evidence indicates that AMH can also activate non-SMAD signaling pathways, including the MAPK/ERK cascade and the PI3K/AKT pathway [59]. These non-canonical pathways contribute to the anti-proliferative and pro-apoptotic effects of AMH in certain cellular contexts. In granulosa cells, AMH has been shown to inhibit FSH-induced cAMP production and downregulate the expression of aromatase (CYP19A1), thereby reducing estrogen biosynthesis [82]. This effect is mediated, at least in part, through the inhibition of FSH receptor signaling at the level of adenylyl cyclase activation.

### 3.3 Role in Male Sexual Differentiation

During male embryogenesis, AMH is secreted by Sertoli cells from approximately week 8 of gestation in humans. The primary function of AMH is to induce the regression of the Müllerian ducts, which are the anlagen of the female reproductive tract (fallopian tubes, uterus, and upper vagina). AMH binds to AMHR2 expressed on the mesenchymal cells surrounding the Müllerian duct epithelium, triggering a signaling cascade that leads to apoptosis of the ductal epithelium and remodeling of the surrounding mesenchyme [34, 48].

The regression of the Müllerian ducts is a tightly regulated process that requires precise temporal and spatial control of AMH expression. The transcription factor SOX9, which is activated by SRY in the developing testis, directly upregulates AMH expression in Sertoli cells [52]. SF1 and GATA4 cooperate with SOX9 to achieve high-level expression, and mutations in any of these transcription factors can lead to impaired AMH production and persistent Müllerian duct syndrome [46].

### 3.4 Role in Ovarian Function and Folliculogenesis

In females, AMH is produced by granulosa cells of pre-antral and small antral follicles, where it functions as a negative regulator of follicular recruitment [2, 78]. AMH inhibits the transition of primordial follicles into the growing follicle pool, thereby preserving the ovarian reserve. The hormone also modulates the sensitivity of growing follicles to FSH, reducing the number of follicles that are selected for ovulation [82].

AMH expression in the ovary is highest in granulosa cells of primary and small pre-antral follicles, and declines as follicles grow and differentiate [78]. The expression is regulated by a complex network of transcription factors, including FOXL2, GATA4, and members of the TGF-β superfamily itself. AMH has been shown to induce the expression of FOXL2 in human granulosa cells, creating a positive feedback loop that reinforces its own expression [69].

### 3.5 Role in Sex Determination Across Vertebrates

The AMH gene has been co-opted as a master sex-determining gene in multiple teleost fish lineages, where a duplicated copy of the gene (amhy) on the Y chromosome determines maleness [7, 11, 13, 27, 67, 70]. This phenomenon has been documented in Japanese flounder (*Paralichthys olivaceus*), Northern pike (*Esox lucius*), lingcod (*Ophiodon elongatus*), and several species of rockfish (*Sebastes* spp.) [11, 13, 67, 70]. In these species, the amhy allele encodes a functional AMH protein that drives testis differentiation, while the autosomal amh copy retains its ancestral function in gonadal development.

The recruitment of AMH as a master sex-determining gene has occurred independently in multiple lineages, suggesting that the gene possesses properties that make it particularly suited for this role [12, 13]. These properties include its early expression in the bipotential gonad, its ability to activate downstream testis differentiation pathways, and its relatively small size, which facilitates duplication and neofunctionalization.

In species lacking Müllerian ducts, such as zebrafish, AMH has evolved novel functions in gonad development and sex determination [38, 75]. Zebrafish amh knockout mutants exhibit defects in germ cell proliferation and gonadal differentiation, indicating that AMH functions beyond its canonical role in Müllerian duct regression [38, 75].

### 3.6 Protein-Protein Interaction Networks

AMH interacts with a limited set of high-affinity binding partners, primarily its receptors and accessory proteins. The mature AMH dimer binds to AMHR2 with high affinity (Kd ~ 1 nM), and this interaction is enhanced by the presence of the pro-domain, which may facilitate receptor dimerization [51]. AMHR2 then recruits a type I receptor, forming a ternary signaling complex.

In addition to its receptors, AMH interacts with extracellular matrix components and circulating binding proteins that modulate its bioavailability. Follistatin and follistatin-related proteins have been shown to bind AMH and inhibit its activity, although the physiological significance of these interactions remains to be fully established [59].

The protein-protein interaction network of AMH, as curated in BioGRID and STRING databases, includes interactions with AMHR2, ACVR1, BMPR1A, BMPR1B, SMAD1, SMAD5, SMAD8, and SMAD4. These interactions form the core of the canonical AMH signaling pathway and are conserved across vertebrates.

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 Persistent Müllerian Duct Syndrome (PMDS)

Persistent Müllerian duct syndrome is a rare autosomal recessive disorder characterized by the presence of Müllerian duct derivatives (uterus, fallopian tubes, and upper vagina) in phenotypically male individuals. PMDS is caused by mutations in either the AMH gene (PMDS type I) or the AMHR2 gene (PMDS type II) [17, 18, 34, 100].

More than 100 distinct AMH mutations have been reported in PMDS patients, including missense, nonsense, frameshift, and splice-site mutations. The mutations are distributed throughout the gene, but certain regions exhibit a higher density of pathogenic variants. The mature domain, particularly the cysteine-knot motif and the receptor-binding interface, is a hotspot for missense mutations that disrupt protein folding or receptor binding [17, 18].

Nonsense and frameshift mutations typically result in complete loss of AMH protein, leading to the classic PMDS phenotype. Missense mutations may cause partial loss of function, resulting in a milder phenotype with variable degrees of Müllerian duct regression [100]. In some cases, compound heterozygous mutations have been identified, where two different mutations in the same gene contribute to the disease phenotype [17].

### 4.2 Premature Ovarian Insufficiency (POI)

Premature ovarian insufficiency is a condition characterized by the cessation of ovarian function before age 40, leading to infertility and estrogen deficiency. While the majority of POI cases are idiopathic, mutations in AMH have been identified in a subset of patients [81].

A study by Mercadal et al. (2015) identified AMH mutations with reduced in vitro bioactivity in patients with POI [81]. These mutations were located in the mature domain and resulted in impaired receptor binding or reduced signaling activity. The clinical phenotype of POI in these patients was variable, with some presenting with primary amenorrhea and others with secondary amenorrhea and declining ovarian reserve.

### 4.3 Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome is a common endocrine disorder affecting 5-10% of women of reproductive age. PCOS is characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology. Serum AMH levels are typically 2-3 times higher in women with PCOS compared to controls, reflecting the increased number of small antral follicles and enhanced AMH production per granulosa cell [1, 5, 50, 72].

The AMH gene has been extensively studied as a candidate gene for PCOS susceptibility. The Ile49Ser polymorphism (rs10407022) has been associated with PCOS in some populations, although the results have been inconsistent across studies [1, 74]. A meta-analysis by Pabalan et al. (2016) found no significant association between the Ile49Ser variant and PCOS risk, but did find an association with reproductive outcomes in women undergoing assisted reproduction [74].

A novel AMH promoter polymorphism, rs10406324, has been associated with lower serum AMH levels in PCOS patients [40]. This variant is located in a putative transcription factor binding site and may reduce AMH promoter activity, partially counteracting the elevated AMH production characteristic of PCOS.

### 4.4 Disorders of Sex Development (DSD)

AMH is an essential component of the diagnostic workup for 46,XY disorders of sex development [34, 46]. Serum AMH levels distinguish between patients with functional testicular tissue (normal or elevated AMH) and those with gonadal dysgenesis or AMH signaling defects (low or undetectable AMH). In patients with persistent Müllerian duct syndrome, AMH levels are low in those with AMH mutations but normal or elevated in those with AMHR2 mutations, reflecting the absence of negative feedback on AMH production [34].

Variants in the AMH gene may also contribute to the broad phenotypic spectrum observed in patients with NR5A1 (SF1) mutations [46]. NR5A1 is a master regulator of AMH expression, and heterozygous NR5A1 variants can cause variable degrees of AMH deficiency, contributing to the clinical heterogeneity of 46,XY DSD.

### 4.5 Other Clinical Associations

AMH levels are used clinically as a biomarker of ovarian reserve and to predict response to controlled ovarian hyperstimulation in assisted reproduction [14, 16, 20, 47]. Low AMH levels are associated with poor ovarian response and reduced pregnancy rates, while high AMH levels are associated with an increased risk of ovarian hyperstimulation syndrome (OHSS) [20, 47].

AMH has also been implicated in the pathogenesis of endometriosis-associated infertility. Polymorphisms in the AMH and AMHR2 genes have been associated with endometriosis risk and severity, although the results have been inconsistent across studies [62]. AMH may also play a role in the regulation of bone metabolism, with recent evidence suggesting that AMH promotes osteoblast differentiation and calcification [79].

## 5. Host-Pathogen & Viral Interactions

### 5.1 Endocrine-Disrupting Chemicals and Environmental Interactions

While AMH is not directly targeted by viral or bacterial pathogens, its expression and function can be modulated by environmental factors, including endocrine-disrupting chemicals (EDCs). Bisphenol A (BPA) and bisphenol S (BPS), which are widely used in plastics manufacturing, have been shown to alter AMH and AMHR2 mRNA expression during bovine oocyte maturation and early embryo development [68]. Exposure to these compounds during critical developmental windows may disrupt AMH signaling and contribute to reproductive disorders.

Estrogenic compounds, including 17β-estradiol and phytoestrogens, have been shown to upregulate AMH expression in granulosa cells [37]. This effect is mediated through estrogen response elements in the AMH promoter and may contribute to the adverse effects of estrogenic EDCs on follicle formation and ovarian reserve [37].

### 5.2 Viral Interactions

There is limited evidence for direct interactions between AMH and viral proteins. However, the AMH promoter is regulated by several transcription factors that are also targeted by viral oncoproteins. For example, the human papillomavirus (HPV) E6 and E7 proteins can modulate the activity of p53 and Rb, which indirectly affect the expression of genes involved in cell cycle regulation and differentiation. Whether these viral proteins influence AMH expression in granulosa cells or Sertoli cells has not been directly investigated.

In the context of viral infections affecting the reproductive tract, such as mumps orchitis or viral oophoritis, inflammation-induced damage to Sertoli cells or granulosa cells can lead to reduced AMH production and impaired reproductive function. The mechanisms underlying these effects involve cytokine-mediated suppression of AMH gene expression and direct cytopathic effects on hormone-producing cells.

### 5.3 Bacterial Infections and Immune Evasion

Bacterial infections of the reproductive tract, such as pelvic inflammatory disease (PID) caused by *Chlamydia trachomatis* or *Neisseria gonorrhoeae*, can lead to tubal damage and infertility. While AMH is not directly involved in the host immune response to these pathogens, the inflammatory milieu associated with chronic infection can suppress AMH production and accelerate the depletion of the ovarian reserve.

The AMH signaling pathway has been implicated in the regulation of immune responses in the gonads. AMH has been shown to modulate the expression of inflammatory cytokines in granulosa cells, and dysregulation of AMH signaling may contribute to the chronic inflammation observed in conditions such as endometriosis and PCOS [72, 98].

## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors

### 6.1 Recombinant AMH as a Therapeutic Agent

Recombinant human AMH (rhAMH) has been investigated as a therapeutic agent for several indications, including fertility preservation and the treatment of ovarian cancer. The rationale for using rhAMH in fertility preservation is based on its ability to inhibit primordial follicle activation, thereby protecting the ovarian reserve from the damaging effects of chemotherapy or radiation [26, 28].

Preclinical studies have demonstrated that rhAMH protects the ovary from doxorubicin-induced damage by regulating cell fate and the response to DNA damage [28]. In mouse models, rhAMH treatment reduced the loss of primordial follicles following chemotherapy and preserved fertility. These findings have led to the development of rhAMH as a candidate for fertility preservation in women undergoing gonadotoxic cancer treatment.

AMH has also been shown to protect against follicle loss in in vitro and in vivo models of ovarian damage [26]. The protective effect is mediated through the downregulation of granulosa cell function and the inhibition of apoptotic pathways.

### 6.2 AMH in Cancer Therapy

AMH and its receptor AMHR2 are expressed in a subset of ovarian cancers, particularly granulosa cell tumors and certain epithelial ovarian cancers [59]. The AMH signaling pathway inhibits cell proliferation and induces apoptosis in AMHR2-positive cancer cells, suggesting that AMH or AMHR2-targeted therapies could be effective in these malignancies.

Several strategies have been explored to exploit the AMH pathway for cancer therapy:

1. **AMH-based cytotoxins:** Fusion proteins consisting of AMH and a cytotoxic moiety (e.g., Pseudomonas exotoxin A) have been designed to selectively kill AMHR2-expressing cancer cells. These immunotoxins have shown efficacy in preclinical models of ovarian cancer.

2. **AMHR2-targeted monoclonal antibodies:** Antibodies directed against AMHR2 have been developed for the delivery of cytotoxic payloads to AMHR2-positive tumors. Antibody-drug conjugates (ADCs) targeting AMHR2 are in preclinical development.

3. **Small-molecule inhibitors of AMH signaling:** In contrast to the pro-apoptotic effects of AMH in cancer cells, inhibition of AMH signaling may be beneficial in conditions where excessive AMH production contributes to pathology, such as PCOS. Small-molecule inhibitors of AMHR2 kinase activity have been identified through high-throughput screening, although none have advanced to clinical trials.

### 6.3 Pharmacogenomics of AMH in Assisted Reproduction

The AMH gene and its receptor are pharmacogenomic targets in the context of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF). AMH levels are used to guide FSH dosing, with low AMH levels indicating the need for higher FSH doses and high AMH levels indicating the need for lower doses to reduce the risk of OHSS [14, 16, 20, 47].

Genetic variants in AMH and AMHR2 have been investigated as predictors of ovarian response to stimulation. The AMHR2 -482 A>G polymorphism has been associated with altered AMH signaling and may influence the response to FSH [16, 74]. However, the clinical utility of AMH genotyping for individualized COH protocols remains to be established, and current guidelines recommend the use of serum AMH levels rather than genetic testing for dose selection [14].

### 6.4 Immunization Strategies

Active immunization against AMH has been explored as a strategy to enhance fertility in livestock species. In Zhedong White geese, immunization against recombinant AMH protein resulted in increased development of pre-ovulatory follicles and improved egg production [45]. This approach has potential applications in poultry and livestock production, where enhancing reproductive efficiency is economically important.

In contrast, passive immunization with AMH-neutralizing antibodies has been proposed as a treatment for conditions associated with elevated AMH levels, such as PCOS. By neutralizing circulating AMH, these antibodies could restore normal follicular development and ovulation in affected women.

## 7. Bioinformatic Resources & Database Accessions

The following table provides key database accessions and bioinformatic resources for the AMH gene and protein.

| **Database** | **Accession/ID** | **Description** |
|---|---|---|
| NCBI Gene | 268 | Gene ID for human AMH |
| Ensembl | ENSG00000104899 | Ensembl gene ID |
| UniProt | P03971 | Protein accession for human AMH |
| RCSB PDB | 1S4Y, 2HGR | Crystal structures of AMH domains |
| HGNC | 464 | HGNC approved symbol |
| OMIM | 600957 | Online Mendelian Inheritance in Man entry |
| ClinVar | Various | Pathogenic variants in AMH |
| RefSeq (mRNA) | NM_000479.4 | Reference mRNA sequence |
| RefSeq (Protein) | NP_000470.2 | Reference protein sequence |
| Gene Ontology (GO) | GO:0005125, GO:0008083, GO:0007179 | Cytokine activity, growth factor activity, TGF-β receptor signaling pathway |
| STRING | 9606.ENSP00000264521 | Protein-protein interaction network |
| BioGRID | 106638 | Interaction data for AMH |
| PharmGKB | PA134935944 | Pharmacogenomic annotations |
| GTEx | ENSG00000104899 | Tissue-specific expression data |

### 7.1 Gene Ontology Annotations

The Gene Ontology (GO) annotations for AMH include:

- **Molecular Function:** GO:0005125 (cytokine activity), GO:0008083 (growth factor activity), GO:0042802 (identical protein binding), GO:0005160 (transforming growth factor beta receptor binding)
- **Biological Process:** GO:0007179 (transforming growth factor beta receptor signaling pathway), GO:0001880 (Müllerian duct regression), GO:0030154 (cell differentiation), GO:0001541 (ovarian follicle development), GO:0007283 (spermatogenesis), GO:0048469 (cell maturation)
- **Cellular Component:** GO:0005576 (extracellular region), GO:0005615 (extracellular space), GO:0032991 (protein-containing complex)

### 7.2 Expression Data

AMH expression is highly tissue-specific, with the highest levels observed in the testis (Sertoli cells) and ovary (granulosa cells). According to GTEx data, AMH expression is also detected at low levels in the pituitary, brain, and adipose tissue. The expression in the pituitary is regulated by GnRH, which transactivates the AMHR2 gene via Egr1 and FOXO1 in gonadotrope cells [19].

### 7.3 Evolutionary Conservation

The AMH gene is highly conserved across vertebrates, with orthologs identified in mammals, birds, reptiles, amphibians, and fish. The mature domain exhibits the highest degree of sequence conservation, consistent with its functional importance in receptor binding and signaling. The pro-domain is less conserved, reflecting its role in protein folding and secretion rather than direct signaling.

In teleost fish, the AMH gene has undergone lineage-specific duplications, with some species harboring multiple copies [7, 13, 92]. These duplications have facilitated the neofunctionalization of AMH as a master sex-determining gene in several lineages, as discussed in Section 3.5.

## Related Clinical & Scientific Guides

* [PMCH Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/pmch-gene-structure-function-pathway)
* [CYLC1 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/cylc1-gene-structure-function-pathway)
* [CRX Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/developmental-biology/crx-gene-structure-function-pathway)


## References

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2. Ramesha, K., Jeyakumar, S., Mall, S., Vedamurthy, G., Kumaresan, A., Devadasn, M.J., Kataktalware, M., Arul, D., Das, D., Manimaran, A. (2022). Anti-Müllerian hormone as an endocrine biomarker of reproductive longevity and assessment of Single Nucleotide Polymorphisms in AMH gene of Bos indicus breeds of cattle. *Reproduction in Domestic Animals*. https://www.semanticscholar.org/paper/534e741ccd0ff1cfa5a43b20d356b7e3bd63fe7d

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