17-31226456-G-C

Variant names:

• chr17-31226456-G-C
• rs779546178
• NM_001042492.3:c.2023G>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4 BP6

The NM_001042492.3(NF1):​c.2023G>C​(p.Gly675Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,522 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G675A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 4.39
• Publications: 0 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3018083).
• BP6: Variant 17-31226456-G-C is Benign according to our data. Variant chr17-31226456-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1321067.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2023G>C	p.Gly675Arg	missense_variant	Exon 18 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.2023G>C	p.Gly675Arg	missense_variant	Exon 18 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2023G>C	p.Gly675Arg	missense_variant	Exon 18 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461522 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727072

African (AFR) AF: 0.00 AC: 0 AN: 33458

American (AMR) AF: 0.00 AC: 0 AN: 44684

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111768

Other (OTH) AF: 0.00 AC: 0 AN: 60368

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Oct 08, 2019

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

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

May 12, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G675R variant (also known as c.2023G>C), located in coding exon 18 of the NF1 gene, results from a G to C substitution at nucleotide position 2023. The glycine at codon 675 is replaced by arginine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Neurofibromatosis, type 1 Benign:1

Feb 27, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.59	D;.;T
Eigen	Benign	0.048
Eigen_PC	Benign	0.18
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Uncertain	0.096	D
MetaRNN	Benign	0.30	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.1	L;L;.
PhyloP100		4.4
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-2.0	N;N;N
REVEL	Benign	0.17
Sift	Uncertain	0.011	D;D;T
Sift4G	Uncertain	0.0060	D;D;D
Polyphen		0.29	B;P;.
Vest4		0.74
MutPred		0.26		Loss of relative solvent accessibility (P = 0.0404);Loss of relative solvent accessibility (P = 0.0404);.;
MVP		0.83
MPC		1.3
ClinPred		0.73	D
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.55
Mutation Taster		=76/24	polymorphism

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

Other links and lift over

dbSNP: rs779546178; hg19: chr17-29553474; COSMIC: COSV100648178; COSMIC: COSV100648178;