Is FLNC p.Arg334Cys (c.1000C>T) pathogenic?

FLNC p.Arg334Cys (c.1000C>T) is classified Conflicting classifications of pathogenicity in FLNC (ClinVar, Conflicting submitters, 6 submitters; last evaluated 2025-08-24). AlphaMissense: likely benign (0.2418); Ultra-rare (popmax 0.016%, afr); Associated with myofibrillar myopathy 5.

What condition is associated with FLNC p.Arg334Cys (c.1000C>T)?

FLNC p.Arg334Cys (c.1000C>T) is associated with myofibrillar myopathy 5, distal myopathy with posterior leg and anterior hand involvement, hypertrophic cardiomyopathy 26 (ClinVar).

How common is FLNC p.Arg334Cys (c.1000C>T) in the general population?

FLNC p.Arg334Cys (c.1000C>T) is ultra-rare (popmax 0.016%, afr) (gnomAD).

How is Muscle filaminopathy inherited?

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

What do computational predictors say about FLNC p.Arg334Cys (c.1000C>T)?

AlphaMissense predicts likely benign (score 0.2418) — an in-silico prediction, not a clinical call.

FLNC p.Arg334Cys

c.1000C>T · rs372497581 · VCV650633

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 6 submitters

AlphaMissense

likely benign

0.2418 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.016%, afr)

Missense predictors

0/2 damaging

AlphaMissense, SaProt · REVEL indeterminate

Conditions

myofibrillar myopathy 5

Computational evidence

Protein change
AlphaMissense	0.2418	likely benign
REVEL	0.331	indeterminate
SaProt	LLR -6.76	tolerated
⇒ AlphaMissense and SaProt both call this tolerated; REVEL is indeterminate.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 4	phastCons 1
Regional constraint	o/e 0.84	unconstrained · MANE · 11 kb · p 8.4e-13 · regional, not allelic
Overall
CADD	24.1	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.016% African / African-American · 12/74,892 alleles

Filtering AF 0.00922% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00722%

Overall 0.00297% 48/1,613,868 alleles · ultra-rare exomes 37/1,461,764 · genomes 11/152,104 · joint denominator

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.016%	6,241
East Asian	0.0111%	8,979
Remaining individualsnot grpmax-eligible	0.0048%	20,822
European (non-Finnish)	0.0022%	45,382
South Asian	0.0022%	45,540

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: FLNC
Protein: p.Arg334Cys
Coding: c.1000C>T
MANE Select: NM_001458
dbSNP: rs372497581
Type: single nucleotide variant
Location: chr7:128838017 (GRCh38)
Gene constraint: LOEUF 0.424 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)

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

Disease context

myofibrillar myopathy 5 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: distal myopathy with posterior leg and anterior hand involvement hypertrophic cardiomyopathy 26

For Muscle filaminopathy (Orphanet):

Inheritance: Autosomal dominant
Onset: Adult

Similar variants

FLNC p.Arg334His Uncertain significance ★★ same residue
FLNC p.Arg334Ser Likely benign ★ ⚠ same residue
FLNC c.1047+1G>T Likely pathogenic ★★ same condition
FLNC c.1048-1G>A Likely pathogenic ★★ same condition
FLNC c.1210+1G>A Likely pathogenic ★★ same condition
FLNC c.1549+2T>G Likely pathogenic ★★ same condition
FLNC c.2007+1G>A Likely pathogenic ★★ same condition
FLNC c.2550+1G>C 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/flnc-p-arg334cys (accessed [today's date]).

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