chr17-31229154-C-G

Variant names:

• chr17-31229154-C-G
• rs753552408
• NM_001042492.3:c.2539C>G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PM5 PP2

The NM_001042492.3(NF1):​c.2539C>G​(p.Leu847Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. L847P) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.70

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 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31229155-T-C is described in Lovd as [Pathogenic].
• PP2: Missense variant in the NF1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 399 curated pathogenic missense variants (we use a threshold of 10). The gene has 143 curated benign missense variants. Gene score misZ: 6.5427 (above the threshold of 3.09). Trascript score misZ: 8.4054 (above the threshold of 3.09). GenCC associations: The gene is linked to neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2539C>G	p.Leu847Val	missense_variant	Exon 21 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2539C>G	p.Leu847Val	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.2539C>G	p.Leu847Val	missense_variant	Exon 21 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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

Jul 10, 2019

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. This sequence change replaces leucine with valine at codon 847 of the NF1 protein (p.Leu847Val). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with NF1-related disease. ClinVar contains an entry for this variant (Variation ID: 569665). Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). A different missense substitution at this codon (p.Leu847Pro) has been determined to be pathogenic (PMID: 10712197, 12552569, 15146469, 23668869, 24413922, 10862084). This suggests that the leucine residue is critical for NF1 protein function and that other missense substitutions at this position may also be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.040
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.69	D;.;T
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Uncertain	0.54	D;D;D
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.5	L;L;.
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-2.1	N;N;N
REVEL	Benign	0.24
Sift	Benign	0.071	T;T;T
Sift4G	Benign	0.12	T;T;T
Polyphen		1.0	D;D;.
Vest4		0.81
MutPred		0.39		Gain of sheet (P = 0.0166);Gain of sheet (P = 0.0166);.;
MVP		0.73
MPC		1.7
ClinPred		0.87	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.43
gMVP		0.63

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs753552408; hg19: chr17-29556172;