# NM_030943.4(AMN):c.1114dup (p.Ala372fs)

https://sugi.bio/variant/amn-p-ala372fs

## Summary

**AMN p.Ala372fs (c.1114dup)** is classified **Pathogenic** in AMN (ClinVar, Single submitter, 1 submitter; last evaluated 2023-03-17). Very rare (popmax 0.000187%, nfe); Associated with Imerslund-Grasbeck syndrome.

**At a glance:** Pathogenic · review: Single submitter · rsID rs921153411 · 1 submitter · 1 linked condition · very rare (popmax 0.000187%, nfe)

## For patients & families {#patients}

This is a change in the AMN gene that is reported as disease-causing, but on limited review, submitted by 1 submitter, and is linked to Imerslund-Grasbeck syndrome.

*Reference information, not medical advice, and not a prediction for any individual. A genetic counselor or clinician can interpret what it means for you and your family.*

|  |  |
| --- | --- |
| Typical inheritance (of this condition) | Autosomal recessive |
| Age of onset (of this condition) | Childhood |
| Prevalence | 1-9 / 1 000 000 (Finland) |
| Diagnostic panels | AMN is a diagnostic-grade gene on 11 Genomics England panels |

**Commonly reported features of Imerslund-Gräsbeck syndrome** (across patients with this condition; presentation varies — frequencies from Orphanet):

- Decreased circulating vitamin B12 concentration — Obligate (100%)
- Malabsorption of Vitamin B12 — Obligate (100%)
- Abnormal blood 5-methyltetrahydrofolate level — Obligate (100%)
- Megaloblastic anemia — Very frequent (99-80%)
- Macrocytic anemia — Very frequent (99-80%)
- Hypersegmentation of neutrophil nuclei — Very frequent (99-80%)
- Proteinuria — Frequent (79-30%)
- Pallor — Frequent (79-30%)

**Support & next steps:** [Condition overview & support (NIH GARD)](https://rarediseases.info.nih.gov/diseases/0007006/index) · [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [AMN](https://sugi.bio/atlas/gene/AMN/) |
| Protein change (HGVS p.) | p.Ala372fs |
| Coding change (HGVS c.) | c.1114dup |
| MANE Select transcript | [NM_030943](https://www.ncbi.nlm.nih.gov/nuccore/NM_030943) |
| dbSNP | [rs921153411](https://www.ncbi.nlm.nih.gov/snp/rs921153411/) |
| Variant type | Duplication |
| Location | chr14:102930270-102930271 (GRCh38) |
| ClinVar | [VCV2839426](https://www.ncbi.nlm.nih.gov/clinvar/variation/2839426/) |

**All HGVS expressions:** `LRG_642:g.12617dup`, `LRG_642t1:c.1114dup`, `NC_000014.8:g.103396609dup`, `NC_000014.9:g.102930272dup`, `NG_008276.2:g.12617dup`, `NG_190975.1:g.355dup`, `NM_001425246.1:c.952dup`, `NM_030943.4:c.1114dup`

## Computational & population evidence {#evidence}

**Concordance:** 1 independent predictor **concordant** with the ClinVar classification.

- **Missense predictors (AlphaMissense/REVEL/SaProt) do not apply** to this variant type — they score amino-acid substitutions only. For non-missense variants the computational signal comes from conservation (below), not from a missing predictor score.
- Conservation: phyloP 2.169, GERP -1.99, phastCons 0.79 — highly conserved position (PP3-type support)
- Molecular consequence: **frameshift** — a predicted loss-of-function variant. Gene population constraint: LOEUF 1.446, pLI 1.8277e-15. *Descriptive; not an applied PVS1 code.*
- Nonsense-mediated decay: the premature termination codon is **in exon 10 of 12**, so the transcript is predicted to undergo NMD.
- CADD: **PHRED 29.0**. No single ClinGen-calibrated threshold exists and the expert panels that use CADD disagree — GUCY2D/AIPL1 require ≥ 20.0 for an untranslated-region variant, ABCA4 ≥ 28.1 for a synonymous or indel variant, the Pulmonary Hypertension panel imports Pejaver 2022's missense-calibrated numbers, and the Antibody Deficiencies panel declines CADD entirely for PIK3CD. CADD v1.7 also incorporates Zoonomia phyloP, so it partly re-expresses the conservation above. *Descriptive; no threshold applied.*
- SpliceAI: **not assessed** — the release is built from a substitutions-only source, so it holds no duplication variants. That is a property of the dataset, not of the variant, and is not evidence against a splicing effect.
- Population frequency (gnomAD v4.1): grpmax **0.000187%** (nfe) · FAF95 3.1e-05% · FAF99 1.2e-05% · 2/1,072,168 in the highest group · 2/1,383,710 alleles overall — very rare (popmax 0.000187%, nfe).

*Computational predictors are not independent (ClinGen Variant Classification guidance): AlphaMissense (Cheng et al. 2023) carries the ACMG weight for missense and conservation (phyloP/GERP/phastCons) for non-missense; REVEL (Pejaver-2022 calibrated strength bands) and SaProt (Su et al. 2023, structure-aware, ClinVar-independent protein language model, raw LLR) are shown as orthogonal agreement signals, not additive. For frequency, the gnomAD v4.1 grpmax filtering allele frequency (FAF95) is ClinGen's designated BA1/BS1 input (gnomAD v4 guidance v3.0, June 2025); BA1/BS1 thresholds are disease-specific, not a blanket 5%. Predictions, not a clinical determination.*

## Gene constraint & dosage {#gene-context}

**AMN** population constraint: LOEUF 1.446, pLI 1.8277e-15, missense-Z -2.732; ClinGen dosage — haploinsufficiency gene assoc. with recessive phenotype, triplosensitivity 0/3. *Lower LOEUF and higher pLI indicate a gene that tolerates loss-of-function poorly; ClinGen dosage is the curated haploinsufficiency call.*

## Protein context {#protein}


AlphaFold model confidence (whole protein): pLDDT 80.78, 61% of residues very-high.

**1 experimental structure(s)** (PDB): [6GJE](https://www.rcsb.org/structure/6GJE).

## What this gene does {#gene-function}

*Describes the biological roles of AMN (the gene this variant disrupts) — not effects measured for this specific variant. A damaging variant is expected to affect these functions and pathways; the degree depends on the variant.*

**How this variant is thought to act:** AMN's established molecular role includes signaling receptor binding. In Reactome, AMN is annotated in disease pathway(s) including **Defective AMN causes MGA1**, **Defective CUBN causes MGA1**.

**Disease mechanism (Reactome):** AMN loss or alteration is curated in [Defective AMN causes MGA1](https://reactome.org/content/detail/R-HSA-3359462), [Defective CUBN causes MGA1](https://reactome.org/content/detail/R-HSA-3359463).

### Pathways affected {#pathways}

AMN participates in **4 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| ⚕ [Defective AMN causes MGA1](https://reactome.org/content/detail/R-HSA-3359462) | other |
| ⚕ [Defective CUBN causes MGA1](https://reactome.org/content/detail/R-HSA-3359463) | other |
| [HDL clearance](https://reactome.org/content/detail/R-HSA-8964011) | other |
| [Uptake of dietary cobalamins into enterocytes](https://reactome.org/content/detail/R-HSA-9758881) | other |

### Molecular function & processes (GO — experimentally supported) {#go}

**Molecular function:** signaling receptor binding, cargo receptor activity.

**Biological process:** receptor-mediated endocytosis, cobalamin metabolic process, cobalamin transport, Golgi to plasma membrane protein transport.

## Clinical significance {#significance}

**Pathogenic** — review status Single submitter *(criteria provided, single submitter)*, last evaluated 2023-03-17.

**Submitter consensus:** unanimous (1/1 Pathogenic).

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Labcorp Genetics (formerly Invitae), Labcorp | Pathogenic | criteria provided, single submitter | clinical testing | 2023-03-17 |

## Associated conditions {#conditions}

[Imerslund-Grasbeck syndrome](https://sugi.bio/atlas/disease/imerslund-grasbeck-syndrome/).

**Reported phenotype names (ClinVar):** Imerslund-Grasbeck syndrome, ENTEROCYTE COBALAMIN MALABSORPTION, ENTEROCYTE INTRINSIC FACTOR RECEPTOR, DEFECT OF, Imerslund-Gräsbeck syndrome, PERNICIOUS ANEMIA, JUVENILE, DUE TO SELECTIVE INTESTINAL MALABSORPTION OF VITAMIN B12, WITH PROTEINURIA, Megaloblastic anemia due to inborn errors of metabolism.

## Similar variants {#similar}

Related AMN variant pages (same residue, condition, or type): [AMN p.Ala372_Leu374dup](/variant/amn-p-ala372-leu374dup), [AMN p.Val442fs](/variant/amn-p-val442fs), [AMN c.1257+20dup](/variant/amn-c-1257-plus-20dup), [AMN p.Gly448_Ala449dup](/variant/amn-p-gly448-ala449dup), [AMN p.Arg388fs](/variant/amn-p-arg388fs), [AMN p.Gln236fs](/variant/amn-p-gln236fs), [AMN p.Leu179fs](/variant/amn-p-leu179fs), [AMN p.Leu419fs](/variant/amn-p-leu419fs).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-14); gnomAD v4.1 (Broad Institute, built 2026-10-14); AlphaMissense (Cheng et al. 2023, © Google DeepMind — CC BY 4.0, built 2026-01-27); REVEL (Ioannidis et al. 2016 — ODbL, built 2026-07-13); SaProt (Su et al. 2023 — MIT, built 2026-10-14); SpliceAI (Illumina — free for non-commercial use, built 2026-10-13); CADD (Rentzsch et al. 2019, University of Washington — free for non-commercial use, built 2026-10-10); Conservation (phyloP/phastCons/GERP) (UCSC hg38 470-way mammal (Hiller Lab) + Ensembl Compara, built 2026-07-12); gnomAD Non-coding Constraint (Gnocchi) (Chen et al. 2024, Broad Institute — CC0, built 2026-10-11); gnomAD Regional Missense Constraint (Broad Institute — CC0, built 2026-10-13); Pangolin (Zeng & Li 2022 — CC BY 4.0, built 2026-10-11); Repeat regions (UCSC — RepeatMasker, TRF, segmental duplications, built 2026-10-11); ClinGen (ClinGen, built 2026-09-22); UniProt (CC BY 4.0); Reactome / GO (CC BY 4.0, built 2026-09-23); MaveDB (per-record license, built 2026-10-11); CIViC (CC0, built 2026-09-22); Orphanet (Orphanet, built 2026-06-12)

*Primary record: NCBI ClinVar (variation 2839426). Classifications reflect these databases as of the page's build date and may change. Free reference use — not medical advice; consult the primary submitters and a clinician.*