17-31229401-T-C

Variant names:

• chr17-31229401-T-C
• rs1555614338
• NM_001042492.3:c.2786T>C

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_001042492.3(NF1):​c.2786T>C​(p.Leu929Pro) 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L929R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.64
• Publications: 1 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 16 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 21 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 chr17-31229401-T-G is described in ClinVar as Pathogenic. ClinVar VariationId is 527514.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.937
• PP5: Variant 17-31229401-T-C is Pathogenic according to our data. Variant chr17-31229401-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 547614.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2786T>C	p.Leu929Pro	missense_variant	Exon 21 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.2786T>C	p.Leu929Pro	missense_variant	Exon 21 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2786T>C	p.Leu929Pro	missense_variant	Exon 21 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:2

Nov 01, 2016

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jun 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense change has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 22190595; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 929 of the NF1 protein (p.Leu929Pro). ClinVar contains an entry for this variant (Variation ID: 547614). For these reasons, this variant has been classified as Pathogenic. 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.

not provided Pathogenic:1

Aug 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NF1: PM2, PM6, PS4:Moderate, PP3

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

Mar 16, 2022

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.L929P variant (also known as c.2786T>C), located in coding exon 21 of the NF1 gene, results from a T to C substitution at nucleotide position 2786. The leucine at codon 929 is replaced by proline, an amino acid with similar properties. This alteration has been identified in individuals with a clinical diagnosis of neurofibromatosis type 1 (NF1) in the literature (Ribeiro MJ et al. Invest Ophthalmol Vis Sci, 2012 Jan;53:287-93; Violante IR et al. Brain, 2013 Mar;136:918-25) and at another laboratory (personal communication). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	27
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.96	D;.;D
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Pathogenic	0.86	D
MutationAssessor	Uncertain	2.4	M;M;.
PhyloP100		7.6
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-5.4	D;D;D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Vest4		0.97
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.92
gMVP		0.95
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs1555614338; hg19: chr17-29556419; COSMIC: COSV62214348; COSMIC: COSV62214348;