17-31260433-A-G

Position:

• chr17-31260433-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM5 PP2 BP4 BS2_Supporting

The NM_001042492.3(NF1):​c.4495A>G​(p.Ile1499Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,722 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1499L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 8.69

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 Uncertain_significance. Variant got 1 ACMG points.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31260433-A-TG is described in ClinVar as [Pathogenic]. Clinvar id is 658301.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.39379504).
• BS2: High AC in GnomAdExome4 at 12 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.4495A>G	p.Ile1499Val	missense_variant	34/58	ENST00000358273.9
NF1	NM_000267.3	c.4432A>G	p.Ile1478Val	missense_variant	33/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.4495A>G	p.Ile1499Val	missense_variant	34/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251294 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135804

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461722 Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7 AN XY: 727160

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: 0.0000116

Gnomad4 FIN exome AF: 0.0000562

Gnomad4 NFE exome AF: 0.00000630

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 18, 2024	This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1478 of the NF1 protein (p.Ile1478Val). This variant is present in population databases (rs764654925, gnomAD 0.002%). This variant has not been reported in the literature in individuals affected with NF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 185497). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on NF1 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 13, 2022

The c.4432A>G (p.I1478V) alteration is located in exon 33 (coding exon 33) of the NF1 gene. This alteration results from a A to G substitution at nucleotide position 4432, causing the isoleucine (I) at amino acid position 1478 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 18, 2014

The p.I1499V variant (also known as c.4495A>G), located in coding exon 34 of the NF1 gene, results from an A to G substitution at nucleotide position 4495. The isoleucine at codon 1499 is replaced by valine, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.01% (greater than 11000 alleles tested) in our clinical cohort. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be benign and tolerated by PolyPhen and SIFT in silico analyses, respectively. Since supporting evidence is limited at this time, the clinical significance of p.I1499V remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.081	D
BayesDel_noAF	Benign	-0.11
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.46	T;.;T
Eigen	Benign	0.093
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Benign	0.39	T;T;T
MetaSVM	Uncertain	-0.26	T
MutationAssessor	Benign	1.2	L;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-0.53	N;N;N
REVEL	Uncertain	0.32
Sift	Benign	0.37	T;T;T
Sift4G	Benign	0.34	T;T;T
Polyphen		0.087	B;P;.
Vest4		0.49
MutPred		0.47		Gain of catalytic residue at I1499 (P = 0.0571);.;.;
MVP		0.72
MPC		1.2
ClinPred		0.42	T
GERP RS		6.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.13
gMVP		0.52

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs764654925; hg19: chr17-29587451;