17-31230260-G-T

Variant names:

• chr17-31230260-G-T
• rs755501749
• NM_001042492.3:c.2991G>T

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM1 PM2 PM5 PP5_Very_Strong

The NM_001042492.3(NF1):​c.2991G>T​(p.Arg997Ser) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R997G) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense, splice_region
• Scores: Splicing: ADA: 0.9801
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 0.393
• Publications: 8 publications found

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 Gene-Disease associations (from GenCC):

• neurofibromatosis type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, PanelApp Australia, G2P, Genomics England PanelApp
• neurofibromatosis-Noonan syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, PanelApp Australia
• Moyamoya disease

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial ovarian cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PM1: In a hotspot region, there are 5 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 chr17-31229974-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 654334.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP5: Variant 17-31230260-G-T is Pathogenic according to our data. Variant chr17-31230260-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 426719.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2991G>T	p.Arg997Ser	missense_variant, splice_region_variant	Exon 23 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.2991G>T	p.Arg997Ser	missense_variant, splice_region_variant	Exon 23 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2991G>T	p.Arg997Ser	missense_variant, splice_region_variant	Exon 23 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:2

May 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 997 of the NF1 protein (p.Arg997Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of NF1-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 426719). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Mar 15, 2022

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:2

Oct 18, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The NF1 c.2991G>T (p.Arg997Ser) variant disrupts a canonical splice-acceptor site and is predicted to interfere with normal NF1 mRNA splicing. This variant has not been reported in individuals with NF1-related conditions in the published literature. This variant has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Based on the available information, this variant is classified as likely pathogenic. -

Mar 28, 2023

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (gnomAD); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 25486365, 2121369, 30274822, 32579932, 25326804, 26689913, 31925297, 27397505, 30287823, 30981987) -

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

Apr 02, 2025

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R997S variant (also known as c.2991G>T) is located in coding exon 23 of the NF1 gene. The arginine at codon 997 is replaced by serine, an amino acid with dissimilar properties. This change occurs in the first base pair of coding exon 23. This variant was determined to be de novo in at least one individual with features consistent with Neurofibromatosis type 1 (Ambry internal data; personal communication). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.87	D;.;T
Eigen	Benign	-0.012
Eigen_PC	Benign	-0.12
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Uncertain	0.63	D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Pathogenic	3.0	M;M;.
PhyloP100		0.39
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-4.2	D;D;D
REVEL	Uncertain	0.36
Sift	Uncertain	0.0020	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.98	D;D;.
Vest4		0.90
MutPred		0.46		Loss of MoRF binding (P = 0.0141);Loss of MoRF binding (P = 0.0141);.;
MVP		0.88
MPC		1.8
ClinPred		1.0	D
GERP RS		-0.84
Varity_R		0.71
gMVP		0.88
Mutation Taster		=12/88	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.98
dbscSNV1_RF	Benign	0.57
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

Other links and lift over

dbSNP: rs755501749; hg19: chr17-29557278; COSMIC: COSV62203559; COSMIC: COSV62203559;