rs863224656

chr17-31221869-A-Gchr17-31221869-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP3

The NM_001042492.3(NF1):c.1661A>G(p.Gln554Arg) variant causes a missense change involving the alteration of a 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q554H) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 8.91

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 13 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, NF1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.783

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.1661A>G	p.Gln554Arg	missense_variant	15/58	ENST00000358273.9
NF1	NM_000267.3	c.1661A>G	p.Gln554Arg	missense_variant	15/57
NF1	NM_001128147.3	c.1661A>G	p.Gln554Arg	missense_variant	15/15

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.1661A>G	p.Gln554Arg	missense_variant	15/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Dec 31, 2022	ClinVar contains an entry for this variant (Variation ID: 216395). 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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on NF1 protein function. This variant has not been reported in the literature in individuals affected with NF1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 554 of the NF1 protein (p.Gln554Arg). -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -

Juvenile myelomonocytic leukemia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

May 22, 2023

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 06, 2020

Missense variants in nearby residues reported in the Human Gene Mutation Database in individuals with Neurofibromatosis type 1 (Stenson et al., 2014); Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes splice predictors and evolutionary conservation, suggests this variant may impact gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 13, 2015

The p.Q554R variant (also known as c.1661A>G), located in coding exon 15 of the NF1 gene, results from an A to G substitution at nucleotide position 1661. The glutamine at codon 554 is replaced by arginine, 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 6497 samples (12994 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.002% (greater than 55000alleles 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.Q554Rremains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
Cadd	Uncertain	24
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.61	D;.;.;T
Eigen	Uncertain	0.66
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D;D;D;D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.78	D;D;D;D
MetaSVM	Benign	-0.31	T
MutationAssessor	Benign	1.7	L;L;L;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Benign	-1.8	N;N;N;N
REVEL	Uncertain	0.30
Sift	Benign	0.060	T;T;D;T
Sift4G	Uncertain	0.018	D;D;T;D
Polyphen		0.88	P;P;.;.
Vest4		0.79
MutPred		0.40		Loss of catalytic residue at Q554 (P = 0.1578);Loss of catalytic residue at Q554 (P = 0.1578);Loss of catalytic residue at Q554 (P = 0.1578);.;
MVP		0.81
MPC		1.7
ClinPred		0.85	D
GERP RS		5.8
Varity_R		0.36
gMVP		0.67

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: rs863224656; hg19: chr17-29548887;