rs1324979194

Positions:

• chr2-39051262-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_005633.4(SOS1):​c.746T>C​(p.Ile249Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,459,024 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SOS1 NM_005633.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.20

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a helix (size 19) in uniprot entity SOS1_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_005633.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.973

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SOS1	NM_005633.4	c.746T>C	p.Ile249Thr	missense_variant	6/23	ENST00000402219.8	NP_005624.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SOS1	ENST00000402219.8	c.746T>C	p.Ile249Thr	missense_variant	6/23	1	NM_005633.4	ENSP00000384675.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251256 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135820

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459024 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 726056

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 01, 2022

The p.I249T variant (also known as c.746T>C), located in coding exon 6 of the SOS1 gene, results from a T to C substitution at nucleotide position 746. The isoleucine at codon 249 is replaced by threonine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

RASopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 22, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 SOS1 protein function. ClinVar contains an entry for this variant (Variation ID: 543967). This missense change has been observed in individual(s) with clinical features of SOS1-related conditions (Invitae). This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 249 of the SOS1 protein (p.Ile249Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D;D;T
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;D;D
M_CAP	Pathogenic	0.54	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.9	M;M;.
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-4.5	D;D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.95
MutPred		0.81		Loss of stability (P = 0.0037);Loss of stability (P = 0.0037);Loss of stability (P = 0.0037);
MVP		0.99
MPC		1.7
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.80
gMVP		0.77

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: rs1324979194; hg19: chr2-39278403;