rs869025501
Variant summary
Our verdict is Uncertain significance. The variant received 9 ACMG points: 9P and 0B. PP2PM2PM1PS3
This summary comes from the ClinGen Evidence Repository: The c.779C>T (p.Thr260Ile) variant in RAF1 was absent from large population databases (PM2; gnomad.broadinstitute.org). It occurs in the CR2 domain of the protein, which has been identified as a region important for protein function (PM1, 29493581). In vitro functional assays indicate that this variant may impact protein function (PS3; PMID:20679480). The variant is located in the RAF1 gene, which has been defined by the ClinGen RASopathy Expert Panel as a gene with a low rate of benign missense variants and pathogenic variants are common (PP2; PMID:29493581). Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. This variant has been observed in multiple probands who lacked consistent RASopathy phenotypes; however, many probands presented with cardiomyopathy (PMID:17603483; Blueprint Genetics internal data, SCV000264163.2; Invitae internal data, SCV000824563.1; Ambry internal data, SCV000740058.2; GeneDx internal data, SCV000582743.4). Although criteria suggest that this variant is likely pathogenic given its location and in vitro functional studies, the lack of clear clinical presentations of a RASopathy phenotype supports that this variant is of uncertain significance at this time. RASopathy-specific ACMG/AMP criteria applied: PS3, PM1, PM2, PP2. LINK:https://erepo.genome.network/evrepo/ui/classification/CA351736/MONDO:0021060/004
Frequency
Consequence
NM_002880.4 missense
Scores
Clinical Significance
Conservation
Publications
- Noonan syndromeInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
- Noonan syndrome 5Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics, PanelApp Australia, G2P
- dilated cardiomyopathy 1NNInheritance: AD Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
- LEOPARD syndrome 2Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Noonan syndrome with multiple lentiginesInheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: Orphanet, ClinGen
- cardiofaciocutaneous syndromeInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
- Costello syndromeInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 9 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 31
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
not provided Pathogenic:2
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Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are often considered pathogenic (HGMD); Published functional studies suggest a damaging effect as the p.(T260I) variant has decreased affinity for C-RAF-PSer, increased enzymatic activity and decreases p.S259 phosphorylation suggestive of an overactive Ras-RAF-MAPK pathway (Molzan et al., 2010); 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, 33686258, 17603483, 33673806, 29493581, 24957944, 9689060, 15520807, 17603482, 19020799, 20679480) -
RASopathy Pathogenic:1Uncertain:1
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. This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 260 of the RAF1 protein (p.Thr260Ile). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Noonan syndrome (PMID: 17603483; Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 222774). Experimental studies have shown that this missense change affects RAF1 function (PMID: 20679480). This variant disrupts the p.Thr260 amino acid residue in RAF1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17603483; Invitae). 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. -
The c.779C>T (p.Thr260Ile) variant in RAF1 was absent from large population databases (PM2; gnomad.broadinstitute.org). It occurs in the CR2 domain of the protein, which has been identified as a region important for protein function (PM1, 29493581). In vitro functional assays indicate that this variant may impact protein function (PS3; PMID: 20679480). The variant is located in the RAF1 gene, which has been defined by the ClinGen RASopathy Expert Panel as a gene with a low rate of benign missense variants and pathogenic variants are common (PP2; PMID: 29493581). Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. This variant has been observed in multiple probands who lacked consistent RASopathy phenotypes; however, many probands presented with cardiomyopathy (PMID: 17603483; Blueprint Genetics internal data, SCV000264163.2; Invitae internal data, SCV000824563.1; Ambry internal data, SCV000740058.2; GeneDx internal data, SCV000582743.4). Although criteria suggest that this variant is likely pathogenic given its location and in vitro functional studies, the lack of clear clinical presentations of a RASopathy phenotype supports that this variant is of uncertain significance at this time. RASopathy-specific ACMG/AMP criteria applied: PS3, PM1, PM2, PP2. -
Primary familial hypertrophic cardiomyopathy Pathogenic:1
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Cardiovascular phenotype Pathogenic:1
The p.T260I variant (also known as c.779C>T), located in coding exon 6 of the RAF1 gene, results from a C to T substitution at nucleotide position 779. The threonine at codon 260 is replaced by isoleucine, an amino acid with similar properties. This alteration is located in the consensus recognition site for 14-3-3, which is a hotspot for Noonan syndrome (NS) mutations. Mutations in this region have been associated with a high prevalence of hypertrophic cardiomyopathy (Pandit B et al. Nat. Genet. 2007;39:1007-12). This variant was identified in one or more individuals with features consistent with RAF1-related RASopathy and segregated with disease in at least one family (Pandit B et al. Nat Genet, 2007 Aug;39:1007-12; Boleti OD et al. Int J Cardiol, 2023 Dec;393:131405; Al-Kouatly HB et al. Genet Med, 2021 Jul;23:1325-1333; Hathaway J et al. BMC Cardiovasc Disord, 2021 Mar;21:126; external communication; Ambry internal data). Functional studies have demonstrated that this alteration leads to decreased phosphorylation of an invariant phosphorylated serine in the 14-3-3 recognition site, impaired 14-3-3 binding affinity, and increased RAF1 catalytic activity (Molzan M et al. Mol. Cell. Biol. 2010;30:4698-711). Other variant(s) at the same codon, p.T260R (c.779C>G), have been identified in individual(s) with features consistent with RAF1-related RASopathy (Pandit B et al. Nat. Genet. 2007;39:1007-12). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at