chr17-31200521-G-C

Variant names:

• chr17-31200521-G-C
• rs199474767
• NM_001042492.3:c.988G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PM5 PP2 PP3_Moderate PP5

The NM_001042492.3(NF1):​c.988G>C​(p.Ala330Pro) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A330T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 9.21

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 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31200522-C-T is described in Lovd as [Likely_pathogenic].
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.896
• PP5: Variant 17-31200521-G-C is Pathogenic according to our data. Variant chr17-31200521-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 404605.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NF1	NM_001042492.3	c.988G>C	p.Ala330Pro	missense_variant	Exon 9 of 58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.988G>C	p.Ala330Pro	missense_variant	Exon 9 of 57		NP_000258.1
NF1	NM_001128147.3	c.988G>C	p.Ala330Pro	missense_variant	Exon 9 of 15		NP_001121619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.988G>C	p.Ala330Pro	missense_variant	Exon 9 of 58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1

Jan 03, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant disrupts the p.Ala330 amino acid residue in NF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17311297, 23913538, 23758643). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. 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. This variant has been reported in an individual affected with neurofibromatosis type 1 (PMID: 27322474). ClinVar contains an entry for this variant (Variation ID: 404605). This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with proline at codon 330 of the NF1 protein (p.Ala330Pro). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and proline. -

not provided Uncertain:1

Jan 04, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 27322474) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	.;D;.;.
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;D;D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.90	D;D;D;D
MetaSVM	Uncertain	0.054	D
MutationAssessor	Uncertain	2.5	M;M;M;M
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-3.7	.;D;D;D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0030	.;D;D;D
Sift4G	Uncertain	0.0020	.;D;D;D
Polyphen		1.0	D;D;D;.
Vest4		0.98, 0.98, 0.97
MutPred		0.61		Gain of relative solvent accessibility (P = 0.0082);Gain of relative solvent accessibility (P = 0.0082);Gain of relative solvent accessibility (P = 0.0082);Gain of relative solvent accessibility (P = 0.0082);
MVP		0.93
MPC		2.0
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.90
gMVP		0.97

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: rs199474767; hg19: chr17-29527539; COSMIC: COSV62201402; COSMIC: COSV62201402;