chr17-31326110-T-A

Variant names:

• chr17-31326110-T-A
• rs876660316
• NM_001042492.3:c.5126T>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001042492.3(NF1):​c.5126T>A​(p.Ile1709Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,132 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. I1709V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.63
• 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: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.903

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.5126T>A	p.Ile1709Lys	missense_variant	Exon 37 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.4	c.5063T>A	p.Ile1688Lys	missense_variant	Exon 36 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.5126T>A	p.Ile1709Lys	missense_variant	Exon 37 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461132 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726800

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33398

American (AMR) AF: 0.00 AC: 0 AN: 44648

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111500

Other (OTH) AF: 0.00 AC: 0 AN: 60364

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:1

Oct 09, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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. This variant has not been reported in the literature in individuals affected with NF1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with lysine at codon 1688 of the NF1 protein (p.Ile1688Lys). The isoleucine residue is moderately conserved and there is a moderate physicochemical difference between isoleucine and lysine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	26
DANN	Benign	0.96
DEOGEN2	Pathogenic	0.90	D;.;T
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.90	D;D;D
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Uncertain	2.0	M;.;.
PhyloP100		7.6
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-5.3	D;D;D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.99	D;D;.
Vest4		0.97
MutPred		0.62		Loss of sheet (P = 0.0011);.;.;
MVP		0.94
MPC		2.3
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.93
gMVP		0.96
Mutation Taster		=9/91	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: rs876660316; hg19: chr17-29653128;