Is AMN p.Ala400= (c.1200T>C) pathogenic?

AMN p.Ala400= (c.1200T>C) is classified Likely benign in AMN (ClinVar, Single submitter, 1 submitter; last evaluated 2023-10-15). Very rare (popmax 0.00202%, nfe); Associated with Imerslund-Grasbeck syndrome.

What condition is associated with AMN p.Ala400= (c.1200T>C)?

AMN p.Ala400= (c.1200T>C) is associated with Imerslund-Grasbeck syndrome (ClinVar).

How common is AMN p.Ala400= (c.1200T>C) in the general population?

AMN p.Ala400= (c.1200T>C) is very rare (popmax 0.00202%, nfe) (gnomAD).

How is Imerslund-Gräsbeck syndrome inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

AMN p.Ala400=

c.1200T>C · rs1410658337 · VCV1110921

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00202%, nfe)

Conditions

Imerslund-Grasbeck syndrome

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -3.7	GERP -2.2
Overall
CADD	1.806	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00202% European (non-Finnish) · 23/1,140,594 alleles

Filtering AF 0.00134% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00112%

Overall 0.00177% 27/1,523,064 alleles · very rare

Ancestry group	Frequency	1 in
Remaining individualsnot grpmax-eligible	0.00676%	14,794
European (non-Finnish)grpmax	0.00202%	49,591

Remaining individuals shows a higher raw frequency than the grpmax group above it. gnomAD excludes bottlenecked groups — Finnish, Ashkenazi Jewish, Amish and “Remaining individuals” — from grpmax, because founder effects make their frequencies unrepresentative for filtering. The table is sorted by frequency, so an excluded group can sit above the grpmax row.

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: AMN
Protein: p.Ala400=
Coding: c.1200T>C
MANE Select: NM_030943
dbSNP: rs1410658337
Type: single nucleotide variant
Location: chr14:102930436 (GRCh38)
Gene constraint: LOEUF 1.446 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 80.78 · 1 PDB

Full AMN gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Imerslund-Grasbeck syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Imerslund-Gräsbeck syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood
Prevalence: 1-9 / 1 000 000 (Finland)

Similar variants

AMN p.Ala400Val Uncertain significance ★★ ⚠ same residue
AMN c.208-1G>C Pathogenic/Likely pathogenic ★★ same condition
AMN c.296-1G>A Likely pathogenic ★★ same condition
AMN c.44-1G>A Likely pathogenic ★★ same condition
AMN c.760+1G>A Likely pathogenic ★★ same condition
AMN c.844-1G>C Likely pathogenic ★★ same condition
AMN p.Thr41Ile Likely pathogenic ★★ ⚠ same condition
AMN p.Trp391Ter Pathogenic/Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/amn-p-ala400 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown