17-31259038-C-G

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_001042492.3(NF1):c.4339C>G(p.Gln1447Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q1447H) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.33

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 19 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31259040-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 233115.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, NF1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.981
• PP5: Variant 17-31259038-C-G is Pathogenic according to our data. Variant chr17-31259038-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 639280.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.4339C>G	p.Gln1447Glu	missense_variant	33/58	ENST00000358273.9
NF1	NM_000267.3	c.4276C>G	p.Gln1426Glu	missense_variant	32/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.4339C>G	p.Gln1447Glu	missense_variant	33/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

This sequence change replaces glutamine, which is neutral and polar, with glutamic acid, which is acidic and polar, at codon 1426 of the NF1 protein (p.Gln1426Glu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with NF1 and clinical features of neurofibromatosis type 1 (NF1) (PMID: 23913538; Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 639280). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt NF1 protein function with a positive predictive value of 95%. This variant disrupts the p.Gln1426 amino acid residue in NF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 26969325; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Jun 22, 2021

In the published literature, this variant has been reported in individuals with Neurofibromatosis type 1 (NF1) or suspected NF1 (PMIDs: 23913538 (2013), 31370276 (2019), and 33443663 (2021)). In addition, this variant has been reported to occur de novo in a symptomatic individual. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is disease causing and damaging. Therefore, the variant is classified as pathogenic. -

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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 16, 2021

The p.Q1426E pathogenic mutation (also known as c.4276C>G), located in coding exon 32 of the NF1 gene, results from a C to G substitution at nucleotide position 4276. The glutamine at codon 1426 is replaced by glutamic acid, an amino acid with highly similar properties. This alteration has been identified in multiple individuals with a clinical diagnosis of neurofibromatosis type 1 (NF1) (Ambry internal data; Sabbagh A et al. Hum Mutat, 2013 Nov;34:1510-8; Giugliano T et al. Genes (Basel), 2019 07;10:). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). Another alteration at the same codon, p.Q1426H (c.4278G>C), has been identified in an individual with a clinical diagnosis of NF1 (Giugliano T et al. Genes (Basel), 2019 07;10:). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
Cadd	Pathogenic	26
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.95	D;.;D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	3.4	M;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-2.5	N;N;D
REVEL	Pathogenic	0.84
Sift	Pathogenic	0.0	D;D;D
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		0.63	P;P;.
Vest4		0.99
MutPred		0.90		Loss of MoRF binding (P = 0.04);.;.;
MVP		0.99
MPC		0.83
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.97
gMVP		0.94

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: rs1135402857; hg19: chr17-29586056;