rs1060500320

Positions:

• chr17-31156018-CA-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.99delA​(p.Val34fs) 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. K33K) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 8.78

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 does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 719 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31156018-CA-C is Pathogenic according to our data. Variant chr17-31156018-CA-C is described in ClinVar as [Pathogenic]. Clinvar id is 404524.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.99delA	p.Val34fs	frameshift_variant	2/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.99delA	p.Val34fs	frameshift_variant	2/57		NP_000258.1
NF1	NM_001128147.3	c.99delA	p.Val34fs	frameshift_variant	2/15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.99delA	p.Val34fs	frameshift_variant	2/58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 10, 2016

For these reasons, this variant has been classified as Pathogenic. While this particular variant has not been reported in the literature, loss-of-function variants in NF1 are known to be pathogenic (PMID: 10712197, 23913538). This sequence change deletes 1 nucleotide from exon 2 of the NF1 mRNA (c.99delA), causing a frameshift at codon 34. This creates a premature translational stop signal (p.Val34Serfs*10) and is expected to result in an absent or disrupted protein product. -

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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 09, 2020

The c.99delA pathogenic mutation, located in coding exon 2 of the NF1 gene, results from a deletion of one nucleotide at nucleotide position 99, causing a translational frameshift with a predicted alternate stop codon (p.V34Sfs*10). The predicted stop codon occurs within the first 150 nucleotides of NF1 gene. This alteration may escape nonsense-mediated mRNAdecay and/or be rescued by re-initiation (Rivas et al. Science. 2015 May 8;348(6235):666-9; Lindeboom et al. Nat Genet. 2016 Oct;48(10):1112-8; Rhee et al. Sci Rep. 2017 May 10;7(1):1653). However, the impacted region is critical for protein function (Ambry internal data). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). 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)		0.0		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: rs1060500320; hg19: chr17-29483036;