Is TTN p.Arg34455Ser (c.103363C>A) pathogenic?

TTN p.Arg34455Ser (c.103363C>A) is classified Uncertain significance in TTN (ClinVar, Single submitter, 1 submitter; last evaluated 2022-08-31). AlphaMissense: likely pathogenic (0.6989); Very rare (popmax 0.00167%, amr); Associated with dilated cardiomyopathy 1G.

What condition is associated with TTN p.Arg34455Ser (c.103363C>A)?

TTN p.Arg34455Ser (c.103363C>A) is associated with dilated cardiomyopathy 1G, autosomal recessive limb-girdle muscular dystrophy type 2J (ClinVar).

How common is TTN p.Arg34455Ser (c.103363C>A) in the general population?

TTN p.Arg34455Ser (c.103363C>A) is very rare (popmax 0.00167%, amr) (gnomAD).

How is Familial isolated dilated cardiomyopathy inherited?

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

What do computational predictors say about TTN p.Arg34455Ser (c.103363C>A)?

AlphaMissense predicts likely pathogenic (score 0.6989) — an in-silico prediction, not a clinical call.

TTN p.Arg34455Ser

c.103363C>A · rs72629785 · VCV1477438

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely pathogenic

0.6989 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00167%, amr)

Conditions

dilated cardiomyopathy 1G

Computational evidence

Protein change
AlphaMissense	0.6989	likely pathogenic
REVEL	0.348	indeterminate
SaProt	—	not scored · why
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 2.6, phastCons 1
Regional constraint	o/e 0.93	unconstrained · MANE · 75 kb · p 3.1e-23 · regional, not allelic
Overall
CADD	20.7	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL is an independent agreement signal.

⚠ Isoform check: AlphaMissense numbered on a different transcript (AM R32814S vs ClinVar R34455S) — verify the residue.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00167% Admixed American · 1/60,016 alleles

Filtering AF 0.000124% ClinGen BA1/BS1 input FAF95, joint · FAF99 9e-05%

Overall 0.000372% 6/1,613,918 alleles · very rare exomes 6/1,461,668 · genomes 0/152,250 · joint denominator

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.00167%	60,016
European (non-Finnish)	0.000424%	235,974

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: TTN
Protein: p.Arg34455Ser
Coding: c.103363C>A
MANE Select: NM_001267550
dbSNP: rs72629785
Type: single nucleotide variant
Location: chr2:178533252 (GRCh38)
Gene constraint: LOEUF 0.479 · pLI <0.01 · ClinGen HI 2/3 (gnomAD)

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

Disease context

dilated cardiomyopathy 1G — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: autosomal recessive limb-girdle muscular dystrophy type 2J

For Familial isolated dilated cardiomyopathy (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive, Mitochondrial inheritance
Onset: All ages
Prevalence: 1-9 / 100 000 (Europe)

Similar variants

TTN p.Arg34455His Uncertain significance ★★ ⚠ same residue
TTN p.Arg34455= Benign/Likely benign ★★ same residue
TTN p.Arg34455Cys Conflicting classifications of pathogenicity ★ same residue
TTN c.100171+1G>A Likely pathogenic ★★ same condition
TTN c.100766-1G>T Likely pathogenic ★★ same condition
TTN c.100766-2A>T Likely pathogenic ★★ same condition
TTN c.106375-2A>G Pathogenic/Likely pathogenic ★★ same condition
TTN c.106531+1G>A 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/ttn-p-arg34455ser (accessed [today's date]).

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