rs56248239
Variant summary
Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBS1_SupportingBS2
The NM_005633.4(SOS1):c.3412A>G(p.Ile1138Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000299 in 1,573,382 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1138K) has been classified as Uncertain significance.
Frequency
Consequence
NM_005633.4 missense
Scores
Clinical Significance
Conservation
Publications
- Noonan syndromeInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
- Noonan syndrome 4Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
- fibromatosis, gingival, 1Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- hereditary gingival fibromatosisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- 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: Benign. The variant received -7 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152186Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000288 AC: 7AN: 242652 AF XY: 0.0000229 show subpopulations
GnomAD4 exome AF: 0.0000303 AC: 43AN: 1421196Hom.: 0 Cov.: 24 AF XY: 0.0000339 AC XY: 24AN XY: 708928 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152186Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4AN XY: 74336 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:2
The c.3412 A>G (I1138V ) variant has not been published as pathogenic or been reported as benign to our knowledge. This variant is observed in 8/268,480 global alleles (0.003%) in large population cohorts (Lek et al., 2016). Multiple in silico splice prediction programs predict that the c.3412 A>G substitution creates a cryptic splice donor site upstream of the canonical splice donor site in intron 22, which may lead to abnormal gene splicing. However, in the absence of functional mRNA studies, the actual effect of this sequence change in this individual is unknown.If expressed and translated, the I1138V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. Additionally, in-silico analyses, including protein predictors and evolutionary conservation, support that this variant does not alter protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is pathogenic or a rare benign variant. -
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not specified Uncertain:1
Variant summary: SOS1 c.3412A>G (p.Ile1138Val) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 3e-05 in 268480 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in SOS1 causing Noonan Syndrome and Related Conditions (3e-05 vs 3e-05), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.3412A>G in individuals affected with Noonan Syndrome and Related Conditions and no experimental evidence demonstrating its impact on protein function have been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Noonan syndrome 4 Uncertain:1
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Cardiovascular phenotype Uncertain:1
The p.I1138V variant (also known as c.3412A>G), located in coding exon 22 of the SOS1 gene, results from an A to G substitution at nucleotide position 3412. The isoleucine at codon 1138 is replaced by valine, an amino acid with highly similar properties. This alteration has been reported in a Noonan syndrome cohort; however, clinical details were limited (Leach NT et al. Genet Med, 2019 02;21:417-425). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Fibromatosis, gingival, 1 Uncertain:1
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RASopathy Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at