rs1060500260

Positions:

• chr17-31214527-A-G
• chr17-31214527-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The ENST00000358273.9(NF1):​c.1469A>G​(p.Lys490Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. K490E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 ENST00000358273.9 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.71

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 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.1469A>G	p.Lys490Arg	missense_variant	13/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.1469A>G	p.Lys490Arg	missense_variant	13/57		NP_000258.1
NF1	NM_001128147.3	c.1469A>G	p.Lys490Arg	missense_variant	13/15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.1469A>G	p.Lys490Arg	missense_variant	13/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

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

Apr 30, 2022

This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 490 of the NF1 protein (p.Lys490Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with NF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 404440). 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 not expected to disrupt NF1 protein function. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 27, 2024

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense 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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 03, 2023

The p.K490R variant (also known as c.1469A>G), located in coding exon 13 of the NF1 gene, results from an A to G substitution at nucleotide position 1469. The lysine at codon 490 is replaced by arginine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.094
BayesDel_addAF	Uncertain	0.025	T
BayesDel_noAF	Benign	-0.20
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.56	.;D;.;.;T
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D;D;D;D;D
M_CAP	Pathogenic	0.46	D
MetaRNN	Uncertain	0.50	D;D;D;D;D
MetaSVM	Benign	-1.2	T
MutationAssessor	Benign	1.2	L;L;L;L;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-1.3	.;N;N;N;N
REVEL	Benign	0.23
Sift	Benign	0.30	.;T;T;T;T
Sift4G	Benign	0.14	.;T;T;T;T
Polyphen		0.079	B;B;D;.;.
Vest4		0.61, 0.59, 0.55
MutPred		0.47		Loss of ubiquitination at K490 (P = 0.0192);Loss of ubiquitination at K490 (P = 0.0192);Loss of ubiquitination at K490 (P = 0.0192);Loss of ubiquitination at K490 (P = 0.0192);.;
MVP		0.73
MPC		1.5
ClinPred		0.76	D
GERP RS		5.3
Varity_R		0.21
gMVP		0.41

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1060500260; hg19: chr17-29541545;