Is MEFV p.Ile40= (c.120C>T) pathogenic?

MEFV p.Ile40= (c.120C>T) is classified Likely benign in MEFV (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-10-17). Very rare (popmax 0.00212%, nfe); Associated with familial Mediterranean fever.

What condition is associated with MEFV p.Ile40= (c.120C>T)?

MEFV p.Ile40= (c.120C>T) is associated with familial Mediterranean fever (ClinVar).

How common is MEFV p.Ile40= (c.120C>T) in the general population?

MEFV p.Ile40= (c.120C>T) is very rare (popmax 0.00212%, nfe) (gnomAD).

How is Familial Mediterranean fever inherited?

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

MEFV p.Ile40=

c.120C>T · rs1454105754 · VCV1147282

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00212%, nfe)

Conditions

familial Mediterranean fever

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 0.16	GERP -4.2, phastCons 0.82
Overall
CADD	3.3	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00212% European (non-Finnish) · 25/1,180,054 alleles

Filtering AF 0.00145% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00123%

Overall 0.00161% 26/1,614,106 alleles · very rare exomes 25/1,461,894 · genomes 1/152,212 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.00212%	47,202
Admixed American	0.00167%	59,988

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: MEFV
Protein: p.Ile40=
Coding: c.120C>T
MANE Select: NM_000243
dbSNP: rs1454105754
Type: single nucleotide variant
Location: chr16:3256468 (GRCh38)
Gene constraint: LOEUF 1.147 · pLI <0.01 · ClinGen HI 0/3 (gnomAD)
Structure: AlphaFold pLDDT 73.64 · 11 PDB
Residue 40: the pyrin domain; an α-helix

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

Disease context

familial Mediterranean fever — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Familial Mediterranean fever (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: >1 / 1000 (Turkey)

Similar variants

MEFV p.Arg761His Pathogenic/Likely pathogenic ★★ ⚠ same condition
MEFV p.Ser242Arg Pathogenic/Likely pathogenic ★★ same condition
MEFV p.Val726Ala Pathogenic/Likely pathogenic ★★ ⚠ same condition
MEFV c.*845C>T Uncertain significance ★★ same condition
MEFV p.Ala193Thr Uncertain significance ★★ ⚠ same condition
MEFV p.Ala2Gly Uncertain significance ★★ ⚠ same condition
MEFV p.Ala416Thr Uncertain significance ★★ ⚠ same condition
MEFV p.Ala768Gly Uncertain significance ★★ ⚠ 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/mefv-p-ile40 (accessed [today's date]).

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