chr3-12604202-C-A

Position:

• chr3-12604202-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PS3_Supporting PM1 PM2_Supporting PS4_Moderate

This summary comes from the ClinGen Evidence Repository: The c.768G>T variant in the RAF1 gene is a missense variant predicted to cause substitution of arginine by serine at amino acid 256 (p.Arg256Ser). This variant is absent from gnomAD 4 (PM2_Supporting). The computational predictor REVEL gives a score of 0.665, which does not meet PP3 or BP4. This variant is located in the CR2 critical functional domain as defined by the ClinGen RASopathy Expert Panel (PM1). This variant has been reported in 3 individuals with clinical features of Noonan syndrome (PS4_Moderate, PMIDs: 17603483, 22190897, 31292302). In vitro functional studies provide some evidence that the p.Arg256Ser variant may impact protein function (PMID:20679480). ERK phosphorylation assay showed that the p.Arg256Ser variant led to significantly increased phosphorylation compared to wild-type (PS3_Supporting; PMID:20679480). In summary, this variant meets criteria to be classified as likely pathogenic for autosomal dominant RASopathies based on ACMG/AMP criteria applied, as specified by the ClinGen RASopathy Variant Curation Expert Panel: PS4_Moderate, PM1, PS3_Supporting, PM2_Supporting (Specification Version 2.1, 9/17/2024) LINK:https://erepo.genome.network/evrepo/ui/classification/CA261625/MONDO:0021060/040

• Frequency: Genomes: not found (cov: 32)
• Consequence: RAF1 NM_002880.4 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:6
• Conservation: PhyloP100: -0.0880

Genes affected

RAF1 (HGNC:9829): (Raf-1 proto-oncogene, serine/threonine kinase) This gene is the cellular homolog of viral raf gene (v-raf). The encoded protein is a MAP kinase kinase kinase (MAP3K), which functions downstream of the Ras family of membrane associated GTPases to which it binds directly. Once activated, the cellular RAF1 protein can phosphorylate to activate the dual specificity protein kinases MEK1 and MEK2, which in turn phosphorylate to activate the serine/threonine specific protein kinases, ERK1 and ERK2. Activated ERKs are pleiotropic effectors of cell physiology and play an important role in the control of gene expression involved in the cell division cycle, apoptosis, cell differentiation and cell migration. Mutations in this gene are associated with Noonan syndrome 5 and LEOPARD syndrome 2. [provided by RefSeq, Jul 2008]

RAF1 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RAF1	NM_002880.4	c.768G>T	p.Arg256Ser	missense_variant	7/17	ENST00000251849.9	NP_002871.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RAF1	ENST00000251849.9	c.768G>T	p.Arg256Ser	missense_variant	7/17	1	NM_002880.4	ENSP00000251849.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:6

Revision: reviewed by expert panel

Submissions by phenotype

RASopathy Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2022	This variant disrupts the p.Arg256 amino acid residue in RAF1. 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. Experimental studies have shown that this missense change affects RAF1 function (PMID: 20679480). 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 RAF1 protein function. ClinVar contains an entry for this variant (Variation ID: 40599). This missense change has been observed in individuals with Noonan syndrome (PMID: 17603483; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 256 of the RAF1 protein (p.Arg256Ser). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 02, 2022	Variant summary: RAF1 c.768G>T (p.Arg256Ser) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251458 control chromosomes (gnomAD). c.768G>T has been reported in the literature in individuals affected with Noonan Syndrome (Pandit_2007, Digilio_2011, Shoji_2019). These data indicate that the variant is likely to be associated with disease. Experimental evidence evaluating an impact on protein function demonstrated the catalytic activity of the variant was significantly increased compared to wild-type, binding of 14-3-3 proteins to C-RAF was impaired and subcellular localization was altered (Molzan_2010). Two ClinVar submitters including an expert panel (ClinGen RASopathy Variant Curation Expert Panel) (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Likely pathogenic, reviewed by expert panel	curation	ClinGen RASopathy Variant Curation Expert Panel	Sep 17, 2024	The c.768G>T variant in the RAF1 gene is a missense variant predicted to cause substitution of arginine by serine at amino acid 256 (p.Arg256Ser). This variant is absent from gnomAD 4 (PM2_Supporting). The computational predictor REVEL gives a score of 0.665, which does not meet PP3 or BP4. This variant is located in the CR2 critical functional domain as defined by the ClinGen RASopathy Expert Panel (PM1). This variant has been reported in 3 individuals with clinical features of Noonan syndrome (PS4_Moderate, PMIDs: 17603483, 22190897, 31292302). In vitro functional studies provide some evidence that the p.Arg256Ser variant may impact protein function (PMID: 20679480). ERK phosphorylation assay showed that the p.Arg256Ser variant led to significantly increased phosphorylation compared to wild-type (PS3_Supporting; PMID:20679480). In summary, this variant meets criteria to be classified as likely pathogenic for autosomal dominant RASopathies based on ACMG/AMP criteria applied, as specified by the ClinGen RASopathy Variant Curation Expert Panel: PS4_Moderate, PM1, PS3_Supporting, PM2_Supporting (Specification Version 2.1, 9/17/2024) -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 03, 2024

Published functional studies demonstrate a damaging effect on protein localization and activity (PMID: 20679480); Not observed in large population cohorts (gnomAD); The majority of missense variants in this gene are considered pathogenic (HGMD); 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: 24803665, 37777071, 24957944, 9689060, 15520807, 17603483, 29493581, 19020799, 20679480) -

Noonan syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Sep 19, 2007

- -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 18, 2023

The c.768G>T (p.R256S) alteration is located in exon 7 (coding exon 6) of the RAF1 gene. This alteration results from a G to T substitution at nucleotide position 768, causing the arginine (R) at amino acid position 256 to be replaced by a serine (S). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been reported as heterozygous in two other individuals with clinical features consistent with RAF1-related RASopathy (Pandit, 2007; Molzan, 2010). Three other alterations at the same codon, c.766A>G (p.R256G), c.767G>A (p.R256K), and c.767G>C (p.R256T) have been detected in affected individuals (Burstein, 2021; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. This variant is located in the conserved region 2 (CR2). The in silico prediction for this alteration is inconclusive. Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D;.;T
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Benign	0.48	N
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Uncertain	0.29	D
MetaRNN	Uncertain	0.73	D;D;D
MetaSVM	Uncertain	-0.011	T
MutationAssessor	Pathogenic	3.0	M;M;.
PrimateAI	Uncertain	0.77	T
PROVEAN	Uncertain	-3.5	D;D;D
REVEL	Pathogenic	0.67
Sift	Uncertain	0.023	D;D;D
Sift4G	Uncertain	0.031	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.78
MutPred		0.54		Gain of glycosylation at S252 (P = 0.0093);Gain of glycosylation at S252 (P = 0.0093);.;
MVP		0.98
MPC		1.4
ClinPred		0.97	D
GERP RS		2.5
Varity_R		0.84
gMVP		0.82

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: rs397516826; hg19: chr3-12645701;