2-39023118-A-C

Position:

• chr2-39023118-A-C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_005633.4(SOS1):​c.1310T>G​(p.Ile437Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,344 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I437T) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SOS1 NM_005633.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 U:1
• Conservation: PhyloP100: 9.19

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 Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-39023118-A-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.936
• PP5: Variant 2-39023118-A-C is Pathogenic according to our data. Variant chr2-39023118-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 181551.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SOS1	NM_005633.4	c.1310T>G	p.Ile437Ser	missense_variant	10/23	ENST00000402219.8	NP_005624.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SOS1	ENST00000402219.8	c.1310T>G	p.Ile437Ser	missense_variant	10/23	1	NM_005633.4	ENSP00000384675.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461344 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726964

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Noonan syndrome 4 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

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not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 24, 2014

p.Ile437Ser (ATT>AGT): c.1310 T>G in exon 10 of the SOS1 gene (NM_005633.3). The I437S mutation was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. I437S is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, size and/or other properties. This substitution occurs at a position that is highly conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. Additionally, missense mutations in the same and nearby residues (G434R, I437N, I437T, C441Y) have been reported in association with Noonan syndrome, supporting the functional importance of this region of the protein. The variant is found in NOONAN panel(s). -

RASopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 25, 2024

This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 437 of the SOS1 protein (p.Ile437Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SOS1-related conditions. ClinVar contains an entry for this variant (Variation ID: 181551). 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 with a positive predictive value of 80%. This variant disrupts the p.Ile437 amino acid residue in SOS1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21387466, 24451042). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Noonan syndrome Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Service de Génétique Moléculaire, Hôpital Robert Debré

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	33
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.92	D;D;T
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;D;D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Uncertain	0.78	D
MutationAssessor	Uncertain	2.6	M;M;.
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-4.9	D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.98	D;D;.
Vest4		0.97
MutPred		0.74		Gain of disorder (P = 0.0072);Gain of disorder (P = 0.0072);Gain of disorder (P = 0.0072);
MVP		0.98
MPC		1.7
ClinPred		1.0	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.92
gMVP		0.94

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: rs397517150; hg19: chr2-39250259;