17-31206307-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_001042492.3(NF1):c.1328T>C(p.Phe443Ser) 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. F443F) 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: 7.62

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.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 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, 0.926
• PP5: Variant 17-31206307-T-C is Pathogenic according to our data. Variant chr17-31206307-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 547588.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.1328T>C	p.Phe443Ser	missense_variant	12/58	ENST00000358273.9
NF1	NM_000267.3	c.1328T>C	p.Phe443Ser	missense_variant	12/57
NF1	NM_001128147.3	c.1328T>C	p.Phe443Ser	missense_variant	12/15

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.1328T>C	p.Phe443Ser	missense_variant	12/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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 Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Mar 28, 2019	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has been observed to be de novo in an individual affected with features consistent with neurofibromatosis, type 1 (Invitae). ClinVar contains an entry for this variant (Variation ID: 547588). This variant is not present in population databases (ExAC no frequency). This sequence change replaces phenylalanine with serine at codon 443 of the NF1 protein (p.Phe443Ser). The phenylalanine residue is highly conserved and there is a large physicochemical difference between phenylalanine and serine. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
Cadd	Pathogenic	28
Dann	Uncertain	1.0
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D
MetaSVM	Uncertain	0.76	D
MutationAssessor	Uncertain	2.2	M;M;M;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.88	D
Polyphen		0.99	D;D;D;.;.
Vest4		0.99, 0.98, 0.98
MutPred		0.67		Gain of disorder (P = 8e-04);Gain of disorder (P = 8e-04);Gain of disorder (P = 8e-04);Gain of disorder (P = 8e-04);.;
MVP		0.98
MPC		2.2
ClinPred		1.0	D
GERP RS		6.2
Varity_R		0.90
gMVP		0.94

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: rs1555611581; hg19: chr17-29533325;