2-39051211-G-T

Variant names:

• chr2-39051211-G-T
• rs137852812
• NM_005633.4:c.797C>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_005633.4(SOS1):​c.797C>A​(p.Thr266Lys) 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T266A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SOS1 NM_005633.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 9.86
• Publications: 25 publications found

Genes affected

SOS1 (HGNC:11187): (SOS Ras/Rac guanine nucleotide exchange factor 1) This gene encodes a protein that is a guanine nucleotide exchange factor for RAS proteins, membrane proteins that bind guanine nucleotides and participate in signal transduction pathways. GTP binding activates and GTP hydrolysis inactivates RAS proteins. The product of this gene may regulate RAS proteins by facilitating the exchange of GTP for GDP. Mutations in this gene are associated with gingival fibromatosis 1 and Noonan syndrome type 4. [provided by RefSeq, Jul 2008]

SOS1 Gene-Disease associations (from GenCC):

• Noonan syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Noonan syndrome 4

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• fibromatosis, gingival, 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• hereditary gingival fibromatosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• cardiofaciocutaneous syndrome

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
• Costello syndrome

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_005633.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-39051211-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1500284.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.844
• PP5: Variant 2-39051211-G-T is Pathogenic according to our data. Variant chr2-39051211-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 12869.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SOS1	NM_005633.4	c.797C>A	p.Thr266Lys	missense_variant	Exon 6 of 23	ENST00000402219.8	NP_005624.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SOS1	ENST00000402219.8	c.797C>A	p.Thr266Lys	missense_variant	Exon 6 of 23	1	NM_005633.4	ENSP00000384675.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

RASopathy Pathogenic:3

-

Baylor Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

Variant classified using ACMG guidelines -

Aug 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with lysine, which is basic and polar, at codon 266 of the SOS1 protein (p.Thr266Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Noonan syndrome (PMID: 17143285, 18678287, 19020799, 19077116, 19953625, 21387466, 22420426, 23665959, 23885229). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 12869). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt SOS1 protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Feb 03, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SOS1 c.797C>A (p.Thr266Lys) results in a non-conservative amino acid change located in the Dbl homology (DH) domain profile (IPR000219) of 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 251356 control chromosomes. c.797C>A has been reported in the literature in individuals affected with Noonan Syndrome (e.g. Denayer_2010, Ferrero_2008, Ko_2008, Roberts_2006), and also observed as de novo in at least one individual. These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 19953625, 18678287, 19020799, 17143285). ClinVar contains an entry for this variant (Variation ID: 12869). Based on the evidence outlined above, the variant was classified as pathogenic. -

Noonan syndrome 4 Pathogenic:2

Nov 01, 2008

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

-

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:2

Aug 23, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 does not alter protein structure/function; This variant is associated with the following publications: (PMID: 35131284, 34184824, 23665959, 24803665, 19953625, 23885229, 17143285, 21387466, 19020799, 18678287, 19077116, 28991257, 30417923, 31560489, 32368696) -

Feb 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

SOS1: PS2:Very Strong, PS4, PM2, PP3 -

Noonan syndrome Pathogenic:2

Dec 12, 2011

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 26, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Thr266Lys variant in SOS1 has been identified in the literature in several i ndividuals with clinical features of Noonan syndrome (Ko 2008, Ferrero 2008, Den ayer 2010, Pierpont 2009, Roberts 2007). This variant has been reported to have occurred de novo in at least one individual with sporadic disease (Denayer 2010) . In summary, this variant meets our criteria to be classified as pathogenic bas ed on it occurring de novo and its high frequency in individuals with features o f Noonan syndrome (http://www.pcpgm.partners.org/lmm). -

Noonan syndrome 1 Pathogenic:1

-

Molecular Genetics, Centre for Human Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Noonan syndrome 4;C4551558:Fibromatosis, gingival, 1 Pathogenic:1

May 18, 2017

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.51	D;D;T
Eigen	Uncertain	0.35
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	.;D;D
M_CAP	Benign	0.079	D
MetaRNN	Pathogenic	0.84	D;D;D
MetaSVM	Uncertain	0.37	D
MutationAssessor	Uncertain	2.2	M;M;.
PhyloP100		9.9
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	-2.3	N;N;N
REVEL	Pathogenic	0.70
Sift	Uncertain	0.010	D;D;D
Sift4G	Uncertain	0.047	D;D;D
Polyphen		0.22	B;B;.
Vest4		0.86
MutPred		0.85		Gain of ubiquitination at T266 (P = 0.0104);Gain of ubiquitination at T266 (P = 0.0104);Gain of ubiquitination at T266 (P = 0.0104);
MVP		0.99
MPC		1.1
ClinPred		0.94	D
GERP RS		5.7
Varity_R		0.46
gMVP		0.89
Mutation Taster		=5/95	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs137852812; hg19: chr2-39278352;