17-31327520-G-T

Variant names:

• chr17-31327520-G-T
• rs778427434
• NM_001042492.3:c.5290G>T

Variant summary

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

The NM_001042492.3(NF1):​c.5290G>T​(p.Val1764Leu) 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 (★★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.56

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 region_of_interest Lipid binding (size 257) in uniprot entity NF1_HUMAN there are 37 pathogenic changes around while only 10 benign (79%) in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the NF1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 399 curated pathogenic missense variants (we use a threshold of 10). The gene has 143 curated benign missense variants. Gene score misZ: 6.5427 (above the threshold of 3.09). Trascript score misZ: 8.4054 (above the threshold of 3.09). GenCC associations: The gene is linked to 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 rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.5290G>T	p.Val1764Leu	missense_variant	Exon 38 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.5227G>T	p.Val1743Leu	missense_variant	Exon 37 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.5290G>T	p.Val1764Leu	missense_variant	Exon 38 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:1

Jul 12, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with NF1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with leucine at codon 1743 of the NF1 protein (p.Val1743Leu). The valine residue is moderately conserved and there is a small physicochemical difference between valine and leucine. ClinVar contains an entry for this variant (Variation ID: 457748). 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). -

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

Nov 16, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.V1743L variant (also known as c.5227G>T), located in coding exon 37 of the NF1 gene, results from a G to T substitution at nucleotide position 5227. The valine at codon 1743 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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	Pathogenic	0.65
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.58	D;.;T
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Uncertain	0.70	D;D;D
MetaSVM	Uncertain	0.12	D
MutationAssessor	Benign	0.95	L;.;.
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-1.7	N;N;N
REVEL	Uncertain	0.56
Sift	Benign	0.23	T;T;T
Sift4G	Benign	0.51	T;T;T
Polyphen		0.33	B;P;.
Vest4		0.79
MutPred		0.48		Loss of sheet (P = 0.0357);.;.;
MVP		0.94
MPC		1.6
ClinPred		0.87	D
GERP RS		6.0
Varity_R		0.56
gMVP		0.62

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs778427434; hg19: chr17-29654538;