CFTR p.Arg334Leu

Variant names:

• chr7-117540231-G-T
• rs397508137
• NM_000492.4:c.1001G>T
• CFTR p.Arg334Leu

Your query was ambiguous. Multiple possible variants found:

• chr7-117540231-G-T
• chr7-117540230-CG-TT
• chr7-117540231-GG-TA
• chr7-117540231-GG-TC
• chr7-117540231-GG-TT
• chr7-117540230-CGG-TTA

GermlineCancer (beta)

Variant summary

Our verdict is Likely pathogenic.

+7 Likely Pathogenic

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 7 classification points (ACGS-UK Somatic Oncogenicity v2025). O1_ModerateO3_SupportingO5_SupportingO6_SupportingO7_SupportingO8_Supporting

The NM_000492.4(CFTR):c.1001G>T (p.Arg334Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The gene CFTR is a tumor suppressor gene (CancerMine: 18 TSG, 1 driver citations). The gene CFTR is a cancer driver gene (CancerMine: 18 TSG, 1 driver citations). The variant allele was found at a cumulative frequency of 0.00000205 (AC=3) in the gnomAD database across 1,461,848 control chromosomes (no homozygotes observed). The grpmax filtering allele frequency (95% CI) is 0.0000147. Note: a gnomAD entry for this variant shows a statistical allele-bias signature, consistent with mosaic/somatic contamination (e.g. age-related clonal hematopoiesis) rather than true inherited population frequency — this frequency should not be read as evidence of a common, benign germline variant. In-silico predictor (REVEL) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 7.60). Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (★★★). ClinVar reports functional evidence for this variant: "SCV001581099: Experimental studies have shown that this missense change affects CFTR function (PMID:12679372, 15130785, 17673962, 30046002)." and additional evidence is available in ClinVar. A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.R334Q: Conflicting_classifications_of_pathogenicity (ClinVar VariationId 53159) Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.R334= (synonymous): Likely_benign (ClinVar VariationId 4868842, 1 star)

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:12 O:1
• Conservation: PhyloP100: 7.60
• Publications: 15 publications found

Genes affected

CFTR (HGNC:1884): (CF transmembrane conductance regulator) This gene encodes a member of the ATP-binding cassette (ABC) transporter superfamily. The encoded protein functions as a chloride channel, making it unique among members of this protein family, and controls ion and water secretion and absorption in epithelial tissues. Channel activation is mediated by cycles of regulatory domain phosphorylation, ATP-binding by the nucleotide-binding domains, and ATP hydrolysis. Mutations in this gene cause cystic fibrosis, the most common lethal genetic disorder in populations of Northern European descent. The most frequently occurring mutation in cystic fibrosis, DeltaF508, results in impaired folding and trafficking of the encoded protein. Multiple pseudogenes have been identified in the human genome. [provided by RefSeq, Aug 2017]

CFTR Gene-Disease associations (from GenCC):

• congenital bilateral aplasia of vas deferens from CFTR mutation

  Inheritance: AR Classification: DEFINITIVE Submitted by: Natera
• cystic fibrosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Myriad Women's Health, ClinGen, Natera, Orphanet
• congenital bilateral absence of vas deferens

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary chronic pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

Classification according to ACGS-UK Somatic Oncogenicity v2025

Classification was made for transcript:

Our verdict: Likely_pathogenic. The variant received 7 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O1Established oncogenic variant		TSG gene: ClinVar germline P/LP ★★+ — Moderate (O1); O1 contributing sources (2.0 pts): ClinVar germline P/LP in TSG (★★★)
	O3Absent or very rare in population		Very rare in gnomAD (popmax AF <0.01%) — O3 supporting; GnomAD effective popmax AF = 0.000015 — very rare (O3 supporting [+1])
	O5Same location/impact as known oncogenic		Different AA at same residue with oncogenic evidence (or germline P/LP in TSG), or same AA change SCI Tier II Potential — Supporting (O5); ClinVar same-AA oncogenic/T1: false | ClinVar same-AA SCI tier: — | CGI same-AA oncogenic: false | TSG: true | ClinVar same-AA germline P/LP: false | CIViC LOF: false | ClinVar diff-AA oncogenic: false | ClinVar diff-AA germline P/LP: true
	O6Computational evidence supports deleterious effect		Computational evidence supports a deleterious/oncogenic effect; Missense variant — primary computational scorer supports an oncogenic/deleterious effect
	O7Mutational hotspot or critical domain		Supporting: cancerhotspots.org hit, critical domain, or missense neighbourhood hotspot; No cancerhotspots.org hit at this position; UniProt domain: 0 pathogenic, 0 benign.; ±8 AA neighbourhood: 3 pathogenic, 0 benign (OR vs. background: 35.0); Variant does not impact splicing — splice-hotspot path not applicable
	O8Missense constraint in gene or region		Missense in gene/domain constrained for missense variation where missense is common disease mechanism (O8 supporting); Gene/disease mechanism: missense is a common mechanism of oncogenesis; gnomAD missense Z-score: -1.07 (threshold ≥3.09 for constraint); Domain-level constraint: variant is in a critically constrained functional domain (IS_AT_CRITICAL_DOMAIN)

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_000492.4. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	CFTR NM_000492.4	MANE Select	c.1001G>T p.Arg334Leu	missense	Exon 8 of 27	Prot: NP_000483.3

CFTR NM_000492.4

MANE Select

HGVSc / HGVSpc.1001G>Tp.Arg334Leu

Exon rankExon 8 of 27

missense

Prot: NP_000483.3

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	CFTR ENST00000003084.11	TSL:1MANE Select	c.1001G>T p.Arg334Leu	missense	Exon 8 of 27	Prot: ENSP00000003084.6 UniProt:
	CFTR ENST00000699602.1		c.1001G>T p.Arg334Leu	missense	Exon 8 of 27	Prot: ENSP00000514471.1 UniProt:
	CFTR ENST00000889206.1		c.1001G>T p.Arg334Leu	missense	Exon 8 of 26	Prot: ENSP00000559265.1 UniProt:

CFTR ENST00000003084.11

TSL:1MANE Select

HGVSc / HGVSpc.1001G>Tp.Arg334Leu

Exon rankExon 8 of 27

missense

Prot: ENSP00000003084.6UniProt: P13569-1

CFTR ENST00000699602.1

HGVSc / HGVSpc.1001G>Tp.Arg334Leu

Exon rankExon 8 of 27

missense

Prot: ENSP00000514471.1UniProt: A0A8V8TNH2

CFTR ENST00000889206.1

HGVSc / HGVSpc.1001G>Tp.Arg334Leu

Exon rankExon 8 of 26

missense

Prot: ENSP00000559265.1UniProt: A0ACI8SBR8

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 4 sources Large-scale international reference populations
GnomAD3 genomes	AF: 0.00000658	AC:1	Hom:0	AN:152044	Cov:32
GnomAD4 exome	AF: 0.00000205	AC:3	Hom:0	AN:1461848	Cov:31
GnomAD4 genome Warning	AF: 0.00000658	AC:1	Hom:0	AN:152044	Cov:32
ALFA (dbGaP/dbSNP Allele Frequency Aggregator)	AF: 0.00	AC:0	Hom:0	AN:109944	Cov:

Showing 4 sources

Case/control cohorts

Cohort	Cases			Controls
	AF	AC	AN	AF	AC	AN
SCHEMA(Schizophrenia)	0.00	0	67870	0.00000750	1	133324

Showing 1 cohortAllele count / allele number. AF is computed from the counts for ASC (not provided by the source).

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
7	-	-	Cystic fibrosis (8)
2	-	-	CFTR-related disorder (2)
1	-	-	Bronchiectasis with or without elevated sweat chloride 1 (1)
1	-	-	Cystic fibrosis;C5924204:CFTR-related disorder (1)
1	-	-	not provided (1)

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
AlphaGenome AVI	Pathogenic	27
AlphaMissense	Pathogenic	0.88
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.61	D
Eigen	Uncertain	0.29
Eigen_PC	Benign	0.22
FATHMM_MKL	Pathogenic	0.98	D
GPN-Star LLR	N/A	-9.1
GPN-Star score	N/A	9.1
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.61	D
Mutation Taster	N/A	2/98	disease causing (ClinVar)
MutationAssessor	Uncertain	2.1	M
PhyloP100	Pathogenic	7.6
popEVE	Benign	-3.2
PrimateAI	Uncertain	0.67	T
PROVEAN	Benign	-1.5	N
REVEL	Pathogenic	0.73
Sift	Benign	0.046	D
Sift4G	Pathogenic	0.0	D
Varity_R	N/A	0.79
VESM-3B	Benign	-8.7

Showing 27 of 27 scores

Splicing Scores

Algorithm	Calibrated pred.	Score	Prediction
Pangolin (max)	Benign	0.0
SpliceAI score (max)	Benign	0.0	Details are displayed if max score is > 0.2

Showing 2 of 2 scores

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

No MaveDB functional evidence found for this variant.

Other links and lift over

dbSNP: rs397508137;

hg19: chr7-117180285;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar