NM_001042492.3:c.1646T>G

Variant names:

• chr17-31221854-T-G
• rs199474758
• NM_001042492.3:c.1646T>G

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Moderate

The NM_001042492.3(NF1):​c.1646T>G​(p.Leu549Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L549P) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.64
• Publications: 0 publications found

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]

NF1 Gene-Disease associations (from GenCC):

• neurofibromatosis type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, PanelApp Australia, G2P, Genomics England PanelApp
• neurofibromatosis-Noonan syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, PanelApp Australia
• Moyamoya disease

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial ovarian cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 28 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31221854-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 68303.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.886
• PP5: Variant 17-31221854-T-G is Pathogenic according to our data. Variant chr17-31221854-T-G is described in ClinVar as Pathogenic. ClinVar VariationId is 2821334.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.1646T>G	p.Leu549Arg	missense_variant	Exon 15 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.1646T>G	p.Leu549Arg	missense_variant	Exon 15 of 57		NP_000258.1
NF1	NM_001128147.3	c.1646T>G	p.Leu549Arg	missense_variant	Exon 15 of 15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.1646T>G	p.Leu549Arg	missense_variant	Exon 15 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Dec 16, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant disrupts the p.Leu549 amino acid residue in NF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10712197, 21520333; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 549 of the NF1 protein (p.Leu549Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with neurofibromatosis type 1 (Invitae). 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. 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	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;.;.;D
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;D;D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.89	D;D;D;D
MetaSVM	Uncertain	0.35	D
MutationAssessor	Uncertain	2.4	M;M;M;.
PhyloP100		7.6
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.8	D;D;D;D
REVEL	Pathogenic	0.76
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	D;D;.;.
Vest4		0.93
MutPred		0.51		Loss of stability (P = 0.043);Loss of stability (P = 0.043);Loss of stability (P = 0.043);.;
MVP		0.94
MPC		2.1
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.89
gMVP		0.98
Mutation Taster		=1/99	disease causing

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

Other links and lift over

dbSNP: rs199474758; hg19: chr17-29548872;