17-31227227-C-G

Variant names:

• chr17-31227227-C-G
• rs1555613912
• NM_001042492.3:c.2261C>G

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2 BP4 BS2_Supporting

The NM_001042492.3(NF1):​c.2261C>G​(p.Ala754Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000116 in 1,461,386 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 7.33

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_benign. Variant got -1 ACMG points.

• PP2: Missense variant in the NF1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 399 curated pathogenic missense variants (we use a threshold of 10). The gene has 143 curated benign missense variants. Gene score misZ: 6.5427 (above the threshold of 3.09). Trascript score misZ: 8.4054 (above the threshold of 3.09). GenCC associations: The gene is linked to neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.
• BP4: Computational evidence support a benign effect (MetaRNN=0.38189813).
• BS2: High AC in GnomAdExome4 at 17 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2261C>G	p.Ala754Gly	missense_variant	Exon 19 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2261C>G	p.Ala754Gly	missense_variant	Exon 19 of 57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2261C>G	p.Ala754Gly	missense_variant	Exon 19 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000116 AC: 17 AN: 1461386 Hom.: 0 Cov.: 31 AF XY: 0.0000124 AC XY: 9 AN XY: 727020

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: 0.0000144

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Mar 15, 2022

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 754 of the NF1 protein (p.Ala754Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with NF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 457576). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt NF1 protein function with a negative predictive value of 95%. 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. -

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

Jul 05, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A754G variant (also known as c.2261C>G), located in coding exon 19 of the NF1 gene, results from a C to G substitution at nucleotide position 2261. The alanine at codon 754 is replaced by glycine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary cancer-predisposing syndrome Uncertain:1

Feb 12, 2022

Sema4, Sema4

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Uncertain	0.027	T
BayesDel_noAF	Benign	-0.20
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.78	D;.;T
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.38	T;T;T
MetaSVM	Benign	-0.77	T
MutationAssessor	Benign	1.7	L;L;.
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-2.5	D;D;N
REVEL	Benign	0.12
Sift	Uncertain	0.017	D;D;D
Sift4G	Uncertain	0.012	D;D;D
Polyphen		0.47	P;B;.
Vest4		0.73
MutPred		0.39		Gain of catalytic residue at A754 (P = 0.0209);Gain of catalytic residue at A754 (P = 0.0209);.;
MVP		0.52
MPC		0.79
ClinPred		0.94	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.42
gMVP		0.43

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs1555613912; hg19: chr17-29554245;