17-31335031-G-C

Position:

• chr17-31335031-G-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP2 PP3_Strong PP5

The NM_001042492.3(NF1):​c.6006G>C​(p.Gln2002His) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q2002P) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 29)
• Consequence: NF1 NM_001042492.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 6.28

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 10 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 16 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, NF1
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-31335031-G-C is Pathogenic according to our data. Variant chr17-31335031-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 487463.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.6006G>C	p.Gln2002His	missense_variant, splice_region_variant	40/58	ENST00000358273.9
NF1	NM_000267.3	c.5943G>C	p.Gln1981His	missense_variant, splice_region_variant	39/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.6006G>C	p.Gln2002His	missense_variant, splice_region_variant	40/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 29

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1 Uncertain:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jul 14, 2021	Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This sequence change replaces glutamine with histidine at codon 1981 of the NF1 protein (p.Gln1981His). The glutamine residue is moderately conserved and there is a small physicochemical difference between glutamine and histidine. This variant also falls at the last nucleotide of exon 39, which is part of the consensus splice site for this exon. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with neurofibromatosis type 1 (Invitae). ClinVar contains an entry for this variant (Variation ID: 487463). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago	Aug 01, 2017	NF1 NM_001042492.2 exon40 p.Gln2002His (c.6006G>C): This variant has not been reported in the literature and is not present in large control databases. Evolutionary conservation and computational predictive tools for this variant are unclear. Of note, a different variant resulting in the same amino acid change at this position has been reported in 1 individual with a clinical suspicion of NF1 (reported as c.5943G>C, p.Gln1981His, Bianchessi 2015 PMID:26740943). In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D;.;T;.
Eigen	Uncertain	0.65
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.78	D;D;D;D
MetaSVM	Pathogenic	0.87	D
MutationAssessor	Uncertain	2.5	M;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.5	D;D;D;.
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0050	D;D;D;.
Sift4G	Uncertain	0.0060	D;D;D;.
Polyphen		0.76	P;D;.;.
Vest4		0.88
MutPred		0.35		Loss of helix (P = 0.1299);.;.;.;
MVP		0.95
MPC		2.3
ClinPred		0.98	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.58
gMVP		0.75

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.66		Position offset: -43
DS_DL_spliceai		0.94		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1555534432; hg19: chr17-29662049;