rs1555619056

Positions:

• chr17-31261858-G-A
• chr17-31261858-G-C
• chr17-31261858-G-T

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.4724+1G>A 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. 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_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.32

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 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.017136151 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31261858-G-A is Pathogenic according to our data. Variant chr17-31261858-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 457713.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.4724+1G>A		splice_donor_variant, intron_variant		ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.4661+1G>A		splice_donor_variant, intron_variant			NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.4724+1G>A		splice_donor_variant, intron_variant		1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 20, 2023	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 457713). Disruption of this splice site has been observed in individuals with symptoms consistent with neurofibromatosistype 1 (NF1) (PMID: 19449407; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 34 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). -

not specified Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Feb 07, 2019

The NF1 c.4724+1G>A variant (c.4661+1G>A for NM_000267.3), to our knowledge, is not described in the medical literature but contains an entry in ClinVar (Variation ID: 457713). It is absent from general population databases (Exome Variant Server and Genome Aggregation Database), indicating it is not a common polymorphism. This variant abolishes the canonical splice donor site of intron 35, which would result in the loss of 49 amino acid residues if a stable protein were produced, leaving the rest of the protein in-frame. Another variant at this nucleotide position (c.4661+1G>C using transcript NM_000267.3) has been described in a family with neurofibromatosis type 1 (NF1) and mRNA analysis of this variant demonstrated aberrant splicing (Thiel 2009). Additional variants that disrupt the canonical splice acceptor site for this exon that are predicted to result in the same protein product have been described in individuals affected with NF1 (Fahsold 2000, Mattocks 2004). Based on available information, c.4724+1G>A is considered likely pathogenic. REFERENCES Fahsold R et al. Minor lesion mutational spectrum of the entire NF1 gene does not explain its high mutability but points to a functional domain upstream of the GAP-related domain. Am J Hum Genet. 2000 Mar;66(3):790-818. Mattocks C et al. Automated comparative sequence analysis identifies mutations in 89% of NF1 patients and confirms a mutation cluster in exons 11-17 distinct from the GAP related domain. J Med Genet. 2004 Apr;41(4):e48. Thiel C et al. Independent NF1 and PTPN11 mutations in a family with neurofibromatosis-Noonan syndrome. Am J Med Genet A. 2009 Jun;149A(6):1263-7. -

Vascular dilatation;C0027830:Neurofibroma Pathogenic:1

Pathogenic, no assertion criteria provided

research

NIHR Bioresource Rare Diseases, University of Cambridge

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.84		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.84		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: rs1555619056; hg19: chr17-29588876; COSMIC: COSV62209406; COSMIC: COSV62209406;