NM_001042492.3:c.1019_1020delCT

Variant names:

• chr17-31200549-ACT-A
• rs1555610903
• NM_001042492.3:c.1019_1020delCT

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001042492.3(NF1):​c.1019_1020delCT​(p.Ser340CysfsTer12) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:13 O:1
• Conservation: PhyloP100: 7.37

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31200549-ACT-A is Pathogenic according to our data. Variant chr17-31200549-ACT-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 547579.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31200549-ACT-A is described in Lovd as [Pathogenic]. Variant chr17-31200549-ACT-A is described in Lovd as [Likely_pathogenic]. Variant chr17-31200549-ACT-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.1019_1020delCT	p.Ser340CysfsTer12	frameshift_variant	Exon 9 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.1019_1020delCT	p.Ser340CysfsTer12	frameshift_variant	Exon 9 of 57		NP_000258.1
NF1	NM_001128147.3	c.1019_1020delCT	p.Ser340CysfsTer12	frameshift_variant	Exon 9 of 15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.1019_1020delCT	p.Ser340CysfsTer12	frameshift_variant	Exon 9 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:13 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:6

Nov 01, 2016

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 20, 2022

MGZ Medical Genetics Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 20, 2019

Medical Genetics, University of Parma

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 26, 2020

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 15, 2022

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ser340Cysfs*12) in the NF1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in NF1 are known to be pathogenic (PMID: 10712197, 23913538). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with neurofibromatosis type 1 (PMID: 9298829, 18546366, 20964122, 31201679, 31370276). This variant is also known as c.1017_c.1018delCT. ClinVar contains an entry for this variant (Variation ID: 547579). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:4

Oct 23, 2020

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 19, 2018

Blueprint Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 13, 2022

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 01, 2021

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (Lek 2016); This variant is associated with the following publications: (PMID: 20964122, 9298829, 18546366, 31370276, 31533797, 31776437) -

Neurofibromatosis, type 1;C4024216:Tibial pseudarthrosis Pathogenic:1

Nov 10, 2018

The Laboratory of Genetics and Metabolism, Hunan Children’s Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Neurofibromatosis-Noonan syndrome Pathogenic:1

Oct 02, 2021

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant (PVS1_VS). It is not observed in the gnomAD v2.1.1 dataset (PM2). The variant has been reported multiple times as an established pathogenic variant (ClinVar ID: VCV000547579.12). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Hereditary cancer-predisposing syndrome;CN230736:Cardiovascular phenotype Pathogenic:1

Jun 13, 2019

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1019_1020delCT variant, located in coding exon 9 of the NF1 gene, results from a deletion of two nucleotides at nucleotide positions 1019 to 1020, causing a translational frameshift with a predicted alternate stop codon (p.S340Cfs*12). This mutation has been detected in one individual who met NIH diagnostic criteria for NF1 (Upadhyaya M, et al. Hum. Mutat. 1997;10(3):248-50). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Neoplasm Other:1

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance: -

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555610903; hg19: chr17-29527567;