chr17-31230268-G-A

Position:

• chr17-31230268-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM5 PP2 PP3_Moderate BS2_Supporting

The NM_001042492.3(NF1):​c.2999G>A​(p.Arg1000His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,460,908 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R1000C) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 9.56

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 4 ACMG points.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31230267-C-T is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), NF1. . Gene score misZ 6.5427 (greater than the threshold 3.09). Trascript score misZ 8.4054 (greater than threshold 3.09). GenCC has associacion of gene with neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.852
• BS2: High AC in GnomAdExome4 at 6 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/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.2999G>A	p.Arg1000His	missense_variant	23/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.2999G>A	p.Arg1000His	missense_variant	23/57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.2999G>A	p.Arg1000His	missense_variant	23/58	1	NM_001042492.3	ENSP00000351015	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460908 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 726762

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: 0.0000187

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Mar 15, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 22, 2024	This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 1000 of the NF1 protein (p.Arg1000His). This variant is present in population databases (rs753082620, 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: 484071). 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) performed at Invitae indicates that this missense variant is expected to disrupt NF1 protein function with a positive predictive value of 95%. This variant disrupts the p.Arg1000 amino acid residue in NF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Juvenile myelomonocytic leukemia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Dec 11, 2023

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 28, 2023

The p.R1000H variant (also known as c.2999G>A), located in coding exon 23 of the NF1 gene, results from a G to A substitution at nucleotide position 2999. The arginine at codon 1000 is replaced by histidine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.85
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.84	D;.;T
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.85	D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.6	M;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-3.5	D;D;D
REVEL	Uncertain	0.53
Sift	Uncertain	0.011	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.91	P;D;.
Vest4		0.82
MutPred		0.51		Loss of MoRF binding (P = 0.0088);Loss of MoRF binding (P = 0.0088);.;
MVP		0.66
MPC		1.9
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.39
gMVP		0.60

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: rs753082620; hg19: chr17-29557286; COSMIC: COSV62197343; COSMIC: COSV62197343;