rs1555534918

Positions:

• chr17-31337845-C-A
• chr17-31337845-C-G
• chr17-31337845-C-T

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.6669C>A​(p.Cys2223Ter) 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 Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 3.00

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 17-31337845-C-A is Pathogenic according to our data. Variant chr17-31337845-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 547678.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-31337845-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.6669C>A	p.Cys2223Ter	stop_gained	44/58	ENST00000358273.9
NF1	NM_000267.3	c.6606C>A	p.Cys2202Ter	stop_gained	43/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.6669C>A	p.Cys2223Ter	stop_gained	44/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

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:3

Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jun 17, 2020	This sequence change creates a premature translational stop signal (p.Cys2202*) in the NF1 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 31370276, 23913538). ClinVar contains an entry for this variant (Variation ID: 547678). Loss-of-function variants in NF1 are known to be pathogenic (PMID: 10712197, 23913538). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Mar 11, 2021	The NF1 c.6606C>A (p.Cys2202*) nonsense variant causes the premature termination of NF1 protein synthesis. It has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, the variant has been reported in individuals with NF1 (PMID: 23913538 (2013)) or clinical features associated with NF1 (PMID: 31370276 (2019)). Based on the available information, this variant is classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Mar 11, 2021	This variant is expected to result in the loss of a functional protein. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). This variant has been identified in at least one individual with clinical features associated with this gene. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	A;A;N;N
Vest4		0.99
ClinPred		1.0	D
GERP RS		2.7

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: rs1555534918; hg19: chr17-29664863; COSMIC: COSV105255157; COSMIC: COSV105255157;