chr17-31259031-G-C

Position:

• chr17-31259031-G-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_001042492.3(NF1):​c.4333-1G>C variant causes a splice acceptor 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.30

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 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.011384976 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.5, offset of 9, new splice context is: ttattgtgtacatacttcAGagt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31259031-G-C is Pathogenic according to our data. Variant chr17-31259031-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 950496.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31259031-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.4333-1G>C		splice_acceptor_variant		ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.4270-1G>C		splice_acceptor_variant			NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.4333-1G>C		splice_acceptor_variant		1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000468 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 06, 2023

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the NF1 protein in which other variant(s) (p.Leu1425Pro) have been determined to be pathogenic (PMID: 10607834, 10712197, 31730495). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. Studies have shown that disruption of this splice site results in the activation of a cryptic splice site in exon 32 (PMID: 23913538). ClinVar contains an entry for this variant (Variation ID: 950496). Disruption of this splice site has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 18800150, 23913538, 33443663). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 31 of the NF1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in the loss of 3 amino acid residue(s), but is expected to preserve the integrity of the reading-frame. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.97		Position offset: 10
DS_AL_spliceai		0.96		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1418965797; hg19: chr17-29586049;