17-31200585-T-C

Position:

• chr17-31200585-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 5P and 2B. PM1 PM2 PP2 BP4_Moderate

The NM_001042492.3(NF1):​c.1052T>C​(p.Val351Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,762 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V351D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 5.67

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 3 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, 16 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, NF1
• BP4: Computational evidence support a benign effect (MetaRNN=0.14816669).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.1052T>C	p.Val351Ala	missense_variant	9/58	ENST00000358273.9
NF1	NM_000267.3	c.1052T>C	p.Val351Ala	missense_variant	9/57
NF1	NM_001128147.3	c.1052T>C	p.Val351Ala	missense_variant	9/15

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.1052T>C	p.Val351Ala	missense_variant	9/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461762 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727186

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 17, 2023	This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 351 of the NF1 protein (p.Val351Ala). 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: 421102). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 06, 2016

This variant is denoted NF1 c.1052T>C at the cDNA level, p.Val351Ala (V351A) at the protein level, and results in the change of a Valine to an Alanine (GTT>GCT). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. NF1 Val351Ala was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Valine and Alanine share similar properties, this is considered a conservative amino acid substitution. NF1 Val351Ala occurs at a position where amino acids with properties similar to Valine are tolerated across species and is not located in a known functional domain. In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available evidence, it is unclear whether NF1 Val351Ala is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

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

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 17, 2023

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.42
CADD	Uncertain	24
DANN	Benign	0.96
Eigen	Benign	-0.35
Eigen_PC	Benign	-0.064
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.88	D;D;D;D;T
M_CAP	Benign	0.064	D
MetaRNN	Benign	0.15	T;T;T;T;T
MetaSVM	Benign	-0.93	T
MutationAssessor	Benign	0.0	N;N;N;N;.
MutationTaster	Benign	0.95	D;D;D
PrimateAI	Uncertain	0.72	T
Polyphen		0.015	B;B;B;.;.
Vest4		0.48, 0.47, 0.49
MutPred		0.62		Gain of relative solvent accessibility (P = 0.0479);Gain of relative solvent accessibility (P = 0.0479);Gain of relative solvent accessibility (P = 0.0479);Gain of relative solvent accessibility (P = 0.0479);.;
MVP		0.40
MPC		0.83
ClinPred		0.71	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.081
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: rs878853861; hg19: chr17-29527603;