17-31227536-C-G

Variant names:

• chr17-31227536-C-G
• rs199474746
• NM_001042492.3:c.2339C>G

Variant summary

Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PM1 PM2 PM5 PP3 PP5_Very_Strong

The NM_001042492.3(NF1):​c.2339C>G​(p.Thr780Arg) 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. 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. T780P) has been classified as Likely 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:9
• Conservation: PhyloP100: 7.38
• Publications: 8 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 15 ACMG points.

• PM1: In a hotspot region, there are 16 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 26 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 chr17-31227535-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1216533.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.838
• PP5: Variant 17-31227536-C-G is Pathogenic according to our data. Variant chr17-31227536-C-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 457581.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.2339C>G	p.Thr780Arg	missense_variant	Exon 20 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.2339C>G	p.Thr780Arg	missense_variant	Exon 20 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2339C>G	p.Thr780Arg	missense_variant	Exon 20 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:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:4

Mar 15, 2022

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 22, 2022

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 01, 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 individuals with neurofibromatosis type 1 (PMID: 16786508, 16944272, 31370276; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with arginine, which is basic and polar, at codon 780 of the NF1 protein (p.Thr780Arg). ClinVar contains an entry for this variant (Variation ID: 457581). 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. This variant disrupts the p.Thr780 amino acid residue in NF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10712197, 11735023, 12552569, 15146469, 16944272, 26478990; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

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

- -

not provided Pathogenic:2

Sep 16, 2018

Gharavi Laboratory, Columbia University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Aug 30, 2022

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with features of neurofibromatosis type (Upadhyaya et al., 2006; Griffiths et al., 2007; Giugliano et al., 2019; Groopman et al., 2019; Hannah-Shmouni et al., 2022); This variant is associated with the following publications: (PMID: 16944272, 25486365, 24803665, 31370276, 30586318, 35456261, 16786508) -

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

Apr 10, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Juvenile myelomonocytic leukemia Pathogenic:1

Apr 26, 2022

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Jan 30, 2024

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T780R variant (also known as c.2339C>G), located in coding exon 20 of the NF1 gene, results from a C to G substitution at nucleotide position 2339. The threonine at codon 780 is replaced by arginine, an amino acid with similar properties. This alteration has been identified in multiple individuals with a clinical diagnosis of neurofibromatosis type 1 (NF1) (Upadhyaya M et al. Hum. Mutat., 2006 Jul;27:716; Griffiths S et al. Fam. Cancer, 2007;6:21-34; Giugliano T et al. Genes (Basel), 2019 07;10; Ambry internal data). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	0.99
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.90	D;.;T
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.84	D;D;D
MetaSVM	Uncertain	-0.14	T
MutationAssessor	Uncertain	2.3	M;M;.
PhyloP100		7.4
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-4.6	D;D;D
REVEL	Uncertain	0.52
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.99
MutPred		0.32		Gain of MoRF binding (P = 0.0368);Gain of MoRF binding (P = 0.0368);.;
MVP		0.90
MPC		1.8
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.86
gMVP		0.94
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		2.0
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

Other links and lift over

dbSNP: rs199474746; hg19: chr17-29554554;