chr17-31248982-A-G

Position:

• chr17-31248982-A-G

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.3975-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,508 control chromosomes in the GnomAD database, with no homozygous occurrence. 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)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: NF1 NM_001042492.3 splice_acceptor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 8.83

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]

NF1 (HGNC:):

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, Cryptic splice site detected, with MaxEntScore 5.3, offset of 5, new splice context is: tttatttttttgtgggttAGaac. Cryptic site results in frameshift 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 17-31248982-A-G is Pathogenic according to our data. Variant chr17-31248982-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 220232.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31248982-A-G is described in Lovd as [Pathogenic]. Variant chr17-31248982-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.3975-2A>G		splice_acceptor_variant, intron_variant		ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.3975-2A>G		splice_acceptor_variant, intron_variant			NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.3975-2A>G		splice_acceptor_variant, intron_variant		1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250764 Hom.: 0 AF XY: 0.00000738 AC XY: 1 AN XY: 135530

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461508 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727074

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome Diagnostics Laboratory, The Hospital for Sick Children	Oct 26, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 08, 2023	This sequence change affects an acceptor splice site in intron 29 of the NF1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in NF1 are known to be pathogenic (PMID: 10712197, 23913538). This variant is present in population databases (no rsID available, gnomAD 0.0009%). Disruption of this splice site has been observed in individuals with neurofibromatosis type 1 (PMID: 10712197, 16786508, 18546366). This variant is also known as IVS23.1-2A>G. ClinVar contains an entry for this variant (Variation ID: 220232). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	NHS Central & South Genomic Laboratory Hub	Nov 11, 2024	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 21, 2023

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); Also known as IVS23.1-2A>G; This variant is associated with the following publications: (PMID: 10712197, 25525159, 9003501, 16786508, 16944272, 18546366, 31776437) -

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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 25, 2024

The c.3975-2A>G intronic pathogenic mutation results from an A to G substitution two nucleotides upstream from coding exon 30 in the NF1 gene. This mutation has been reported in multiple individuals with neurofibromatosis type 1 and has been found to cause aberrant mRNA splicing (Upadhyaya M et al. Hum. Genet., 1997 Jan;99:88-92; Fahsold R et al. Am. J. Hum. Genet., 2000 Mar;66:790-818; Griffiths S et al. Fam. Cancer, 2007;6:21-34; Upadhyaya M et al. Hum. Mutat., 2006 Jul;27:716; Pros E et al. Hum. Mutat., 2008 Sep;29:E173-93; Ambry internal data). In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.010
CADD	Pathogenic	35
DANN	Uncertain	0.98
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Uncertain	0.90	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.83		Position offset: 7
DS_AL_spliceai		0.99		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs864622431; hg19: chr17-29576000; COSMIC: COSV62194646;