NM_001042492.3:c.3497G>C

Variant names:

• chr17-31233002-G-C
• rs199474787
• NM_001042492.3:c.3497G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_001042492.3(NF1):​c.3497G>C​(p.Gly1166Ala) variant causes a missense, splice region 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1166D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.56
• 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: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 36 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 chr17-31232881-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1731988.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.3497G>C	p.Gly1166Ala	missense_variant, splice_region_variant	Exon 27 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.3497G>C	p.Gly1166Ala	missense_variant, splice_region_variant	Exon 27 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.3497G>C	p.Gly1166Ala	missense_variant, splice_region_variant	Exon 27 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Mar 25, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G1166A variant (also known as c.3497G>C), located in coding exon 27 of the NF1 gene, results from a G to C substitution at nucleotide position 3497. This variant impacts the first base pair of coding exon 27. The glycine at codon 1166 is replaced by alanine, an amino acid with similar 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Uncertain	0.053	T
BayesDel_noAF	Benign	-0.16
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D;.;T
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.81	D;D;D
MetaSVM	Benign	-1.2	T
MutationAssessor	Benign	1.1	L;L;.
PhyloP100		9.6
PrimateAI	Pathogenic	0.93	D
PROVEAN	Uncertain	-2.9	D;D;D
REVEL	Uncertain	0.33
Sift	Benign	0.088	T;T;T
Sift4G	Uncertain	0.013	D;D;D
Polyphen		0.14	B;D;.
Vest4		0.87
MutPred		0.74		Loss of catalytic residue at L1167 (P = 0.0866);Loss of catalytic residue at L1167 (P = 0.0866);.;
MVP		0.67
MPC		1.8
ClinPred		0.75	D
GERP RS		5.7
Varity_R		0.25
gMVP		0.58
Mutation Taster		=15/85	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.070		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: rs199474787; hg19: chr17-29560020;