rs1131691079

Positions:

• chr17-31338022-C-A
• chr17-31338022-C-G
• chr17-31338022-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The NM_001042492.3(NF1):​c.6705-3C>A variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.9993
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 2.20

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 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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 17-31338022-C-A is Pathogenic according to our data. Variant chr17-31338022-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 481981.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.6705-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000358273.9
NF1	NM_000267.3	c.6642-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.6705-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	UAB Medical Genomics Laboratory, UAB Medicine	Jan 20, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 14, 2022	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. This variant disrupts the c.6642-3C nucleotide in the NF1 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 25074460, 31730495, 32126153). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant is associated with altered splicing resulting in a premature truncation (PMID: 32126153). ClinVar contains an entry for this variant (Variation ID: 481981). This variant has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 32126153). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 43 of the NF1 gene. It does not directly change the encoded amino acid sequence of the NF1 protein. It affects a nucleotide within the consensus splice site. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, Medical University Innsbruck	Jan 20, 2020	- -

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 07, 2017

The c.6642-3C>A intronic variant results from a C to A substitution 3 nucleotides upstream from coding exon 44 in the NF1 gene. This alteration has been reported in 1 of 279 prospectively analyzed patients in routine diagnosis for NF1 (Pasmant E et al. Eur. J. Hum. Genet., 2015 May;23:596-601). This nucleotide position is well conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to abolish the native splice acceptor site; however, direct evidence is unavailable. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.34
CADD	Benign	17
DANN	Uncertain	0.99

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.87
SpliceAI score (max)		0.82		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.82		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1131691079; hg19: chr17-29665040;