17-31326033-C-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PS1 PM1 PM2 PP2 PP3 PP5_Moderate

The NM_001042492.3(NF1):c.5049C>G(p.Asn1683Lys) 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 pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another nucleotide change resulting in same amino acid change has been previously reported as Pathogenicin ClinVar. Synonymous variant affecting the same amino acid position (i.e. N1683N) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 1.39

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 Pathogenic. Variant got 12 ACMG points.

• PS1: Transcript NM_001042492.3 (NF1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 2736555
• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 15 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, NF1
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-31326033-C-G is Pathogenic according to our data. Variant chr17-31326033-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 655745.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-31326033-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.5049C>G	p.Asn1683Lys	missense_variant	37/58	ENST00000358273.9
NF1	NM_000267.3	c.4986C>G	p.Asn1662Lys	missense_variant	36/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.5049C>G	p.Asn1683Lys	missense_variant	37/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Oct 13, 2023

This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 1662 of the NF1 protein (p.Asn1662Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 24676943, 27322474; Invitae). ClinVar contains an entry for this variant (Variation ID: 655745). 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 expected to disrupt NF1 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Uncertain	0.023	T
BayesDel_noAF	Benign	-0.20
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D;.;D
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.90	D;D;D
MetaSVM	Benign	-0.28	T
MutationAssessor	Uncertain	2.8	M;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-5.4	D;D;D
REVEL	Pathogenic	0.86
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.78		Gain of methylation at N1683 (P = 5e-04);.;.;
MVP		0.85
MPC		1.9
ClinPred		1.0	D
GERP RS		1.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.64		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.64		Position offset: -5

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs140994965; hg19: chr17-29653051;