17-31229956-T-C

Position:

• chr17-31229956-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The ENST00000358273.9(NF1):​c.2972T>C​(p.Met991Thr) 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M991V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 ENST00000358273.9 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.64

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 uncertain in ENST00000358273.9
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31229956-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 941469.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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.894

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2972T>C	p.Met991Thr	missense_variant	22/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2972T>C	p.Met991Thr	missense_variant	22/57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2972T>C	p.Met991Thr	missense_variant	22/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 21, 2016

This sequence change replaces methionine with threonine at codon 991 of the NF1 protein (p.Met991Thr). The methionine residue is moderately conserved and there is a moderate physicochemical difference between methionine and threonine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a NF1-related disease. In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. 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: "Possibly Damaging"; Align-GVGD: "Class C0"). -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 08, 2021

The p.M991T variant (also known as c.2972T>C), located in coding exon 22 of the NF1 gene, results from a T to C substitution at nucleotide position 2972. The methionine at codon 991 is replaced by threonine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.53
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.070
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.83	D;.;T
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.89	D;D;D
MetaSVM	Benign	-1.2	T
MutationAssessor	Uncertain	2.0	M;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-3.9	D;D;D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.0020	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.77	P;P;.
Vest4		0.88
MutPred		0.66		Loss of helix (P = 0.0196);Loss of helix (P = 0.0196);.;
MVP		0.86
MPC		1.6
ClinPred		0.97	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.71
gMVP		0.90

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: rs1060500298; hg19: chr17-29556974;