17-31227526-T-C

Position:

• chr17-31227526-T-C

Variant summary

Our verdict is Pathogenic. Variant got 25 ACMG points: 25P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_001042492.3(NF1):​c.2329T>C​(p.Trp777Arg) 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 Likely pathogenic (★★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W777G) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 7.49

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 25 ACMG points.

• PS1: Transcript NM_001042492.3 (NF1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 230937
• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 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 chr17-31227526-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 635519.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, 0.938
• PP5: Variant 17-31227526-T-C is Pathogenic according to our data. Variant chr17-31227526-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 652361.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31227526-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.2329T>C	p.Trp777Arg	missense_variant	20/58	ENST00000358273.9
NF1	NM_000267.3	c.2329T>C	p.Trp777Arg	missense_variant	20/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.2329T>C	p.Trp777Arg	missense_variant	20/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:4

Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 27, 2019	Not observed in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 27322474, 16005615, 24803665) -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2023	NF1: PS1, PM2, PM5, PS4:Moderate -

Neurofibromatosis, type 1 Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Sep 01, 2023	This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with neurofibromatosis type 1 (PMID: 16005615, 22034633, 27322474). It has also been observed to segregate with disease in related individuals. This variant is also known as c.2540T>C. ClinVar contains an entry for this variant (Variation ID: 652361). 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. For these reasons, this variant has been classified as Pathogenic. This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 777 of the NF1 protein (p.Trp777Arg). -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	NHS Central & South Genomic Laboratory Hub	Jul 01, 2024	- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 01, 2020

The p.W777R variant (also known as c.2329T>C), located in coding exon 20 of the NF1 gene, results from a T to C substitution at nucleotide position 2329. The tryptophan at codon 777 is replaced by arginine, an amino acid with dissimilar properties. This mutation has been identified in multiple individuals with a clinical diagnosis of neurofibromatosis type 1 (NF1) (Cai Y et al. J. Dermatol. Sci., 2005 Aug;39:125-7; Evans DG et al. EBioMedicine, 2016 May;7:212-20; Pasmant E et al. J. Natl. Cancer Inst., 2011 Nov;103:1713-22; Sabbagh A et al. Hum. Mutat., 2013 Nov;34:1510-8; Ambry internal data). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). 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	1.0
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;.;D
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Uncertain	-0.24	T
MutationAssessor	Uncertain	2.4	M;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-11	D;D;D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.72		Gain of disorder (P = 0.0151);Gain of disorder (P = 0.0151);.;
MVP		0.91
MPC		2.3
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.97

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: rs876658853; hg19: chr17-29554544;