chr17-31221930-G-C

Variant names:

• chr17-31221930-G-C
• rs1131691096
• ENST00000431387.8:c.1722G>C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001042492.3(NF1):​c.1721+1G>C variant causes a splice donor, intron 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. 1/1 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_donor, intron
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.28

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 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31221930-G-C is Pathogenic according to our data. Variant chr17-31221930-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 586169.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31221930-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.1721+1G>C		splice_donor_variant, intron_variant	Intron 15 of 57	ENST00000358273.9	NP_001035957.1
NF1	NM_001128147.3	c.1722G>C	p.Arg574Ser	missense_variant	Exon 15 of 15		NP_001121619.1
NF1	NM_000267.3	c.1721+1G>C		splice_donor_variant, intron_variant	Intron 15 of 56		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.1721+1G>C		splice_donor_variant, intron_variant	Intron 15 of 57	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:2

Mar 15, 2022

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 15 of the NF1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or altered protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with neurofibromatosis type 1 (PMID: 12552569, 18546366, 23913538). This variant is also known as exon 11. ClinVar contains an entry for this variant (Variation ID: 586169). Studies have shown that disruption of this splice site results in skipping of exon 15 (also known as exon 11 in the literature), and produces a non-functional protein and/or introduces a premature termination codon (PMID: 23913538). For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:2

Apr 09, 2018

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 06, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 18546366, 12552569, 23913538) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Benign	-0.39
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Uncertain	0.66
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Pathogenic	0.76	D
ClinPred		0.99	D
GERP RS		5.8

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.87		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.87		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: rs1131691096; hg19: chr17-29548948;