rs1135402788

Positions:

• chr17-31169905-CTG-C

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.496_497delGT​(p.Val166fs) 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 Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. V166V) has been classified as Pathogenic. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 8.72

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 (HGNC:):

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 17-31169905-CTG-C is Pathogenic according to our data. Variant chr17-31169905-CTG-C is described in ClinVar as [Pathogenic]. Clinvar id is 431562.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31169905-CTG-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.496_497delGT	p.Val166fs	frameshift_variant	5/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.496_497delGT	p.Val166fs	frameshift_variant	5/57		NP_000258.1
NF1	NM_001128147.3	c.496_497delGT	p.Val166fs	frameshift_variant	5/15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.496_497delGT	p.Val166fs	frameshift_variant	5/58	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

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Jun 01, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	Medical Genetics, University of Parma	Feb 02, 2017	- -
Pathogenic, no assertion criteria provided	research	Division of Human Genetics, National Health Laboratory Service/University of the Witwatersrand	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 18, 2023	This sequence change creates a premature translational stop signal (p.Val166Leufs*7) 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: 10726756, 18041031). ClinVar contains an entry for this variant (Variation ID: 431562). For these reasons, this variant has been classified as Pathogenic. -

Gastric cancer Pathogenic:1

Pathogenic, no assertion criteria provided

research

Laboratory for Genotyping Development, RIKEN

Jul 01, 2021

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Sep 21, 2022

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 (gnomAD); This variant is associated with the following publications: (PMID: 10726756, 18041031, 32554297, 32980694, 23913538, 30287823) -

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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 24, 2022

The c.496_497delGT pathogenic mutation, located in coding exon 5 of the NF1 gene, results from a deletion of two nucleotides at nucleotide positions 496 to 497, causing a translational frameshift with a predicted alternate stop codon (p.V166Lfs*7). This mutation was detected in multiple unrelated individuals with neurofibromatosis type 1 (Fahsold R et al. Am J Hum Genet, 2000 Mar;66:790-818; Yoshida Y et al. J Dermatol, 2018 Mar;45:363-364; Shi L et al. Stem Cell Res, 2020 07;46:101842). 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. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1135402788; hg19: chr17-29496923;