rs138186428

chr17-31235769-C-Gchr17-31235769-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_001042492.3(NF1):c.3867C>G(p.Phe1289Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. F1289C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.820

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 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, NF1

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.3867C>G	p.Phe1289Leu	missense_variant	28/58	ENST00000358273.9
NF1	NM_000267.3	c.3867C>G	p.Phe1289Leu	missense_variant	28/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.3867C>G	p.Phe1289Leu	missense_variant	28/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 19, 2017

The F1289L variant in the NF1 gene has not, to our knowledge, been published in the literature as pathogenic or benign. This variant 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. Since Phenylalanine and Leucine share similar properties, this is considered a conservative amino acid substitution. The F1289L variant occurs at a position that is conserved across species and is located in Ras-GAP domain (Uniprot). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available evidence, we consider F1289L to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 22, 2014

The p.F1289L variant (also known as c.3867C>G), located in coding exon 28 of the NF1 gene, results from a C to G substitution at nucleotide position 3867. The phenylalanine at codon 1289 is replaced by leucine, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.003% (greater than 30000alleles tested) in our clinical cohort.This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis.Since supporting evidence is limited at this time, the clinical significance of p.F1289Lremains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
Cadd	Benign	21
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D;.;T
Eigen	Benign	-0.060
Eigen_PC	Benign	-0.023
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Pathogenic	0.75	D
MetaRNN	Uncertain	0.74	D;D;D
MetaSVM	Benign	-0.45	T
MutationAssessor	Benign	0.42	N;N;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-4.8	D;D;D
REVEL	Uncertain	0.52
Sift	Uncertain	0.013	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		0.41	B;P;.
Vest4		0.89
MutPred		0.65		Loss of methylation at K1290 (P = 0.0298);Loss of methylation at K1290 (P = 0.0298);.;
MVP		0.92
MPC		1.5
ClinPred		0.98	D
GERP RS		1.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.86
gMVP		0.65

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: rs138186428; hg19: chr17-29562787;