17-31226453-A-G

Position:

• chr17-31226453-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_001042492.3(NF1):​c.2020A>G​(p.Ser674Gly) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,520 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict 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. S674R) 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: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.85

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 1 ACMG points.

• 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=0.08792633).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.2020A>G	p.Ser674Gly	missense_variant	18/58	ENST00000358273.9
NF1	NM_000267.3	c.2020A>G	p.Ser674Gly	missense_variant	18/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.2020A>G	p.Ser674Gly	missense_variant	18/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461520 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727076

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 19, 2017	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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glycine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with NF1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with glycine at codon 674 of the NF1 protein (p.Ser674Gly). The serine residue is moderately conserved and there is a small physicochemical difference between serine and glycine. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 06, 2020

The p.S674G variant (also known as c.2020A>G), located in coding exon 18 of the NF1 gene, results from an A to G substitution at nucleotide position 2020. The serine at codon 674 is replaced by glycine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. 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	0.069
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.64
CADD	Benign	16
DANN	Uncertain	0.98
DEOGEN2	Benign	0.41	T;.;T
Eigen	Benign	-0.44
Eigen_PC	Benign	-0.21
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.76	T;T;T
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.088	T;T;T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	-0.69	N;N;.
MutationTaster	Benign	0.94	D;D
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	0.090	N;N;N
REVEL	Benign	0.059
Sift	Benign	0.11	T;T;T
Sift4G	Benign	1.0	T;T;T
Polyphen		0.0050	B;B;.
Vest4		0.13
MutPred		0.19		Loss of glycosylation at S674 (P = 0.0224);Loss of glycosylation at S674 (P = 0.0224);.;
MVP		0.31
MPC		0.63
ClinPred		0.34	T
GERP RS		4.8
Varity_R		0.064
gMVP		0.26

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: rs1555613753; hg19: chr17-29553471;