rs1555619033

Variant names:

• chr17-31261801-T-TA
• rs1555619033
• NM_001042492.3:c.4669dupA

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.4669dupA​(p.Thr1557AsnfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,576 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.69

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 17-31261801-T-TA is Pathogenic according to our data. Variant chr17-31261801-T-TA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 503769.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.4669dupA	p.Thr1557AsnfsTer7	frameshift_variant	Exon 35 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.4606dupA	p.Thr1536AsnfsTer7	frameshift_variant	Exon 34 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.4669dupA	p.Thr1557AsnfsTer7	frameshift_variant	Exon 35 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460576 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726572

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

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

Sep 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Thr1536Asnfs*7) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with neurofibromatosis type 1 (PMID: 26740943). ClinVar contains an entry for this variant (Variation ID: 503769). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Mar 15, 2022

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 01, 2016

Center for Human Genetics, Inc, Center for Human Genetics, Inc

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Nov 14, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4606dupA variant in the NF1 gene has been reported previously in association with NF1 (Bianchessi et al., 2015). The duplication causes a frameshift starting with codon Threonine 1536, changes this amino acid to an Asparagine residue and creates a premature Stop codon at position 7 of the new reading frame, denoted p.Thr1536AsnfsX7. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The variant is not observed in large population cohorts (Lek et al., 2016). In summary, we consider this variant to be pathogenic. -

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

Jan 03, 2018

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4606dupA pathogenic mutation, located in coding exon 34 of the NF1 gene, results from a duplication of A at nucleotide position 4606, causing a translational frameshift with a predicted alternate stop codon (p.T1536Nfs*7). This mutation has been reported in an Italian patient with a clinical diagnosis of neurofibromatosis type 1 (Bianchessi D et al. Mol Genet Genomic Med 2015 Nov;3(6):513-25). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs1555619033; hg19: chr17-29588819;