rs864622300

chr17-31182662-T-Achr17-31182662-T-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.885T>A(p.Asn295Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. N295S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 2.32

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 where missense usually causes diseases, NF1
• BP4: Computational evidence support a benign effect (MetaRNN=0.13157466).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.885T>A	p.Asn295Lys	missense_variant	8/58	ENST00000358273.9
NF1	NM_000267.3	c.885T>A	p.Asn295Lys	missense_variant	8/57
NF1	NM_001128147.3	c.885T>A	p.Asn295Lys	missense_variant	8/15

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.885T>A	p.Asn295Lys	missense_variant	8/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000227

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Dec 19, 2023	This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 295 of the NF1 protein (p.Asn295Lys). 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. This missense change has been observed to co-occur in individuals with a different variant in NF1 that has been determined to be pathogenic (Invitae), but the significance of this finding is unclear. ClinVar contains an entry for this variant (Variation ID: 219894). 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 with a negative predictive value of 95%. 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. -

Neurofibromatosis, type 1;C0349639:Juvenile myelomonocytic leukemia;C0553586:Café-au-lait macules with pulmonary stenosis;C1834235:Neurofibromatosis, familial spinal;C2931482:Neurofibromatosis-Noonan syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 04, 2021

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 15, 2020

The p.N295K variant (also known as c.885T>A), located in coding exon 8 of the NF1 gene, results from a T to A substitution at nucleotide position 885. The asparagine at codon 295 is replaced by lysine, an amino acid with similar properties. This amino acid position is highly 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	Uncertain	0.52
BayesDel_addAF	Benign	-0.095	T
BayesDel_noAF	Benign	-0.37
Cadd	Benign	18
Dann	Benign	0.81
Eigen	Benign	-0.65
Eigen_PC	Benign	-0.49
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.93	D;D;D;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Benign	0.13	T;T;T;T;T
MetaSVM	Benign	-0.93	T
MutationAssessor	Benign	0.58	N;N;N;N;.
MutationTaster	Benign	0.99	D;D;D
PrimateAI	Uncertain	0.73	T
Polyphen		0.88	P;B;B;.;.
Vest4		0.71, 0.69, 0.78
MutPred		0.29		Loss of loop (P = 0.0203);Loss of loop (P = 0.0203);Loss of loop (P = 0.0203);Loss of loop (P = 0.0203);.;
MVP		0.62
MPC		0.90
ClinPred		0.21	T
GERP RS		0.32
Varity_R		0.084
gMVP		0.37

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: rs864622300; hg19: chr17-29509680;