17-31229455-C-G

Position:

• chr17-31229455-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The ENST00000358273.9(NF1):​c.2840C>G​(p.Ser947Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,418 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S947T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 ENST00000358273.9 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.54

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 Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in ENST00000358273.9
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), NF1. . Gene score misZ 6.5427 (greater than the threshold 3.09). Trascript score misZ 8.4054 (greater than threshold 3.09). GenCC has associacion of gene with neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.
• BP4: Computational evidence support a benign effect (MetaRNN=0.3349309).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2840C>G	p.Ser947Cys	missense_variant	21/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2840C>G	p.Ser947Cys	missense_variant	21/57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2840C>G	p.Ser947Cys	missense_variant	21/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461418 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727020

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on NF1 protein function. ClinVar contains an entry for this variant (Variation ID: 237542). This variant has not been reported in the literature in individuals affected with NF1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 947 of the NF1 protein (p.Ser947Cys). -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 10, 2021

The c.2840C>G (p.S947C) alteration is located in exon 21 (coding exon 21) of the NF1 gene. This alteration results from a C to G substitution at nucleotide position 2840, causing the serine (S) at amino acid position 947 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.084
BayesDel_addAF	Benign	-0.0052	T
BayesDel_noAF	Benign	-0.25
CADD	Uncertain	24
DANN	Benign	0.97
DEOGEN2	Pathogenic	0.81	D;.;T
Eigen	Uncertain	0.21
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Benign	0.082	D
MetaRNN	Benign	0.33	T;T;T
MetaSVM	Benign	-0.82	T
MutationAssessor	Benign	1.6	L;L;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-2.7	D;D;N
REVEL	Benign	0.098
Sift	Benign	0.056	T;T;D
Sift4G	Uncertain	0.033	D;D;D
Polyphen		0.088	B;B;.
Vest4		0.36
MutPred		0.45		Loss of catalytic residue at S947 (P = 0.0528);Loss of catalytic residue at S947 (P = 0.0528);.;
MVP		0.53
MPC		0.78
ClinPred		0.77	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.16
gMVP		0.19

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: rs878853879; hg19: chr17-29556473;