17-31181760-C-G

Position:

• chr17-31181760-C-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.705C>G​(p.Tyr235Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Y235Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 2.21

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: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-31181760-C-G is Pathogenic according to our data. Variant chr17-31181760-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 186943.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31181760-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.705C>G	p.Tyr235Ter	stop_gained	7/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.705C>G	p.Tyr235Ter	stop_gained	7/57		NP_000258.1
NF1	NM_001128147.3	c.705C>G	p.Tyr235Ter	stop_gained	7/15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.705C>G	p.Tyr235Ter	stop_gained	7/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Suma Genomics, Suma Genomics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 27, 2023	For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 186943). This premature translational stop signal has been observed in individual(s) with clinical features of neurofibromatosis (PMID: 18546366). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Tyr235*) in the NF1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in NF1 are known to be pathogenic (PMID: 10712197, 23913538). -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 26, 2014

The p.Y235* pathogenic mutation (also known as c.705C>G) located in coding exon 7 of the NF1 gene, results from a C to G substitution at nucleotide position 705. This changes the amino acid from a tyrosine to a stop codon within coding exon 7. This alteration has previously been identified in individuals with clinical features consistent with neurofibromatosis type 1 (NF1) (<span style="background-color: initial;">Pros E, Hum. Mutat. 2008 Sep; 29(9):E173-93; Pasmant E, Eur. J. Hum. Genet. 2014 Jul).<span style="background-color: initial;">In addition to the clinical data presented in the literature, since<span style="background-color: initial;">premature stop codons are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.61	D
BayesDel_noAF	Pathogenic	0.63
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Uncertain	0.88	D
MutationTaster	Benign	1.0	A;A;A
Vest4		0.95, 0.97
GERP RS		5.9

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs769048538; hg19: chr17-29508778; COSMIC: COSV62215531;