rs769891933

chr2-39014774-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_005633.4(SOS1):c.1931T>C(p.Ile644Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000144 in 1,392,428 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:4
• Conservation: PhyloP100: 8.92

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.814

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SOS1	NM_005633.4	c.1931T>C	p.Ile644Thr	missense_variant	11/23	ENST00000402219.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SOS1	ENST00000402219.8	c.1931T>C	p.Ile644Thr	missense_variant	11/23	1	NM_005633.4	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000800 AC: 2 AN: 250028 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 135406

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000291

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000328

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000144 AC: 2 AN: 1392428 Hom.: 0 Cov.: 23 AF XY: 0.00000287 AC XY: 2 AN XY: 696742

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000119

Gnomad4 FIN exome AF: 0.0000188

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 15, 2020

Variant summary: SOS1 c.1931T>C (p.Ile644Thr) results in a non-conservative amino acid change located in the Ras-like guanine nucleotide exchange factor, N-terminal domain (IPR000651) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 250028 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1931T>C in individuals affected with Noonan Syndrome And Related Conditions and no experimental evidence demonstrating its impact on protein function have been reported. A ClinVar submitter (evaluation after 2014) cites the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Noonan syndrome 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

-

- -

Fibromatosis, gingival, 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

-

- -

RASopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 25, 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 not expected to disrupt SOS1 protein function. ClinVar contains an entry for this variant (Variation ID: 411869). This variant has not been reported in the literature in individuals affected with SOS1-related conditions. This variant is present in population databases (rs769891933, gnomAD 0.003%). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 644 of the SOS1 protein (p.Ile644Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Benign	-0.031	T
BayesDel_noAF	Benign	-0.18
Cadd	Pathogenic	26
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.71	D;D;D
Eigen	Uncertain	0.30
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Benign	0.022	T
MetaRNN	Pathogenic	0.81	D;D;D
MetaSVM	Benign	-0.80	T
MutationAssessor	Benign	1.5	L;L;.
MutationTaster	Benign	0.98	D;D;D
PrimateAI	Pathogenic	0.80	D
PROVEAN	Uncertain	-2.9	D;D;D
REVEL	Benign	0.29
Sift	Uncertain	0.011	D;D;D
Sift4G	Uncertain	0.017	D;D;D
Polyphen		0.15	B;B;.
Vest4		0.75
MutPred		0.72		Loss of stability (P = 0.0043);Loss of stability (P = 0.0043);Loss of stability (P = 0.0043);
MVP		0.53
MPC		0.86
ClinPred		0.89	D
GERP RS		5.8
Varity_R		0.54
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: rs769891933; hg19: chr2-39241915;