NM_001042492.3:c.839_840delTAinsCG

Variant names:

• chr17-31182616-TA-CG
• NM_001042492.3:c.839_840delTAinsCG
• NF1 p.Ile280Thr

GermlineCancer (beta)

Variant summary

Our verdict is Uncertain significance.

+2 Uncertain · Warm

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 2 classification points (ACGS-UK Somatic Oncogenicity v2025). O3_Moderate

The NM_001042492.3(NF1):c.839_840delTAinsCG (p.Ile280Thr) variant causes a missense change. The gene NF1 is a tumor suppressor gene (CancerMine: 101 TSG, 30 oncogene, 95 driver citations). The gene NF1 is a known oncogene (CancerMine: 101 TSG, 30 oncogene, 95 driver citations). The gene NF1 is a cancer driver gene (CancerMine: 101 TSG, 30 oncogene, 95 driver citations). Note: allele frequency estimates from gnomAD may be inaccurate for this variant type (MNP or indel longer than 3 bp) due to technology limitations. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.I280T: Uncertain_significance (ClinVar VariationId 517245, 1 star) This exact variant is curated in the UniProt human variants database as Uncertain Significance, associated with Adenomas and Adenocarcinomas; it is also listed as a COSMIC curated somatic variant.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.14
• Publications: 0 publications found

Genes affected

NF1 (HGNC:7765): (neurofibromin 1) This gene product appears to function as a negative regulator of the ras signal transduction pathway. Mutations in this gene have been linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. The mRNA for this gene is subject to RNA editing (CGA>UGA->Arg1306Term) resulting in premature translation termination. Alternatively spliced transcript variants encoding different isoforms have also been described for this gene. [provided by RefSeq, Jul 2008]

NF1 Gene-Disease associations (from GenCC):

• neurofibromatosis type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen, G2P, Genomics England PanelApp
• neurofibromatosis-Noonan syndrome

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• Moyamoya disease

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial ovarian cancer

  Inheritance: Unknown Classification: NO_KNOWN Submitted by: ClinGen

Classification according to ACGS-UK Somatic Oncogenicity v2025

Classification was made for transcript:

Our verdict: Uncertain_significance. The variant received 2 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O3Absent or very rare in population		Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = absent, AC = 0 — absent/extremely rare (O3 moderate [+2])

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_001042492.3. 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
	NF1 NM_001042492.3	MANE Select	c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: NP_001035957.1 UniProt:
	NF1 NM_000267.4		c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: NP_000258.1 UniProt:
	NF1 NM_001128147.3		c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: NP_001121619.1 UniProt:

NF1 NM_001042492.3

MANE Select

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: NP_001035957.1UniProt: P21359-1

NF1 NM_000267.4

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: NP_000258.1UniProt: P21359-2

NF1 NM_001128147.3

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: NP_001121619.1UniProt: P21359-5

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	NF1 ENST00000358273.9	TSL:1MANE Select	c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: ENSP00000351015.4 UniProt:
	NF1 ENST00000356175.7	TSL:1	c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: ENSP00000348498.3 UniProt:
	NF1 ENST00000431387.8	TSL:1	c.839_840delTAinsCG p.Ile280Thr	missense	N/A	Prot: ENSP00000412921.4 UniProt:

NF1 ENST00000358273.9

TSL:1MANE Select

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: ENSP00000351015.4UniProt: P21359-1

NF1 ENST00000356175.7

TSL:1

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: ENSP00000348498.3UniProt: P21359-2

NF1 ENST00000431387.8

TSL:1

HGVSc / HGVSpc.839_840delTAinsCGp.Ile280Thr

Exon rankN/A

missense

Prot: ENSP00000412921.4UniProt: P21359-5

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 2 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:32
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:32

Showing 2 sources

ClinVar

Not reported in ClinVar

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
PhyloP100	Uncertain	7.1

Showing 1 of 1 scores

Splicing Scores

No splicing scores have been computed for this variant.

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

hg19: chr17-29509634;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar