chr17-31338008-G-A

Position:

• chr17-31338008-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3 PP5

The NM_001042492.3(NF1):​c.6705-17G>A variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000693 in 1,443,792 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 splice_polypyrimidine_tract, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:2
• Conservation: PhyloP100: 0.671

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-31338008-G-A is Pathogenic according to our data. Variant chr17-31338008-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 422739.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=2, Likely_pathogenic=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.6705-17G>A		splice_polypyrimidine_tract_variant, intron_variant		ENST00000358273.9
NF1	NM_000267.3	c.6642-17G>A		splice_polypyrimidine_tract_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.6705-17G>A		splice_polypyrimidine_tract_variant, intron_variant		1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.93e-7 AC: 1 AN: 1443792 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 719514

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: 0.00

Gnomad4 OTH exome AF: 0.0000167

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:3 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	UAB Medical Genomics Laboratory, UAB Medicine	Jan 20, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 30, 2023	In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Studies have shown that this variant is associated with altered splicing resulting in unknown protein product impact (PMID: 32126153). ClinVar contains an entry for this variant (Variation ID: 422739). 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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, Medical University Innsbruck	Jan 20, 2020	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 10, 2016

This variant is denoted NF1 c.6642-17G>A or IVS43-17G>A and consists of a G>A nucleotide substitution at the -17 position of intron 43 of the NF1 gene. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. In silico models are uninformative, and in the absence of RNA or functional studies, the actual effect of this variant is unknown. NF1 c.6642-17G>A was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. The guanine (G) nucleotide that is altered is not conserved across species. Based on currently available information, it is unclear whether NF1 c.6642-17G>A is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
CADD	Benign	0.081
DANN	Benign	0.59

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.75		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.75		Position offset: 17

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

Publications

LitVar

Other links and lift over

dbSNP: rs1064795966; hg19: chr17-29665026; COSMIC: COSV62201913; COSMIC: COSV62201913;