17-31226517-T-C

Position:

• chr17-31226517-T-C

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_001042492.3(NF1):​c.2084T>C​(p.Leu695Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,592 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/21 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. L695R) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 7.53

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 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31226517-T-G is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), NF1. . Gene score misZ 6.5427 (greater than the threshold 3.09). Trascript score misZ 8.4054 (greater than threshold 3.09). GenCC has associacion of gene with neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.947
• PP5: Variant 17-31226517-T-C is Pathogenic according to our data. Variant chr17-31226517-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 68309.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31226517-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2084T>C	p.Leu695Pro	missense_variant	18/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2084T>C	p.Leu695Pro	missense_variant	18/57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2084T>C	p.Leu695Pro	missense_variant	18/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461592 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727108

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Genome Diagnostics Laboratory, The Hospital for Sick Children	Oct 26, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Mar 26, 2022	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. ClinVar contains an entry for this variant (Variation ID: 68309). This missense change has been observed in individual(s) with neurofibromatosis type-1 (PMID: 10712197, 23404336, 23758643, 26331193; Invitae). In at least one individual the variant was observed to be de novo. 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 695 of the NF1 protein (p.Leu695Pro). -

not provided Pathogenic:1 Other:1

Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Sep 06, 2023	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; This variant is associated with the following publications: (PMID: 26331193, 10712197, 24803665, 23404336, 22190595, 23758643, 25486365) -
not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 06, 2022

The p.L695P variant (also known as c.2084T>C), located in coding exon 18 of the NF1 gene, results from a T to C substitution at nucleotide position 2084. The leucine at codon 695 is replaced by proline, an amino acid with similar properties. This alteration has been identified in multiple individuals with a clinical diagnosis of neurofibromatosis type 1 (Fahsold R et al. Am J Hum Genet, 2000 Mar;66:790-818; Ribeiro MJ et al. Invest Ophthalmol Vis Sci, 2012 Jan;53:287-93; Violante IR et al. Brain, 2013 Mar;136:918-25; Abdolrahimzadeh S et al. Ophthalmic Genet, 2016 06;37:214-6). 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	1.0
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	27
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.96	D;.;D
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Uncertain	0.11	D
MutationAssessor	Uncertain	2.4	M;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-5.5	D;D;D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		1.0
MutPred		0.80		Loss of helix (P = 0.0033);Loss of helix (P = 0.0033);.;
MVP		0.98
MPC		2.2
ClinPred		1.0	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.96
gMVP		0.97

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

Publications

LitVar

Other links and lift over

dbSNP: rs199474761; hg19: chr17-29553535; COSMIC: COSV100648305; COSMIC: COSV100648305;