15-48437347-G-C
Variant summary
Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM2PP2PP3_ModeratePP5_Very_Strong
The NM_000138.5(FBN1):c.6354C>G(p.Ile2118Met) variant causes a missense change involving the alteration of a non-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 Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. I2118I) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000138.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 13 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 31
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Marfan syndrome Pathogenic:1
The p.Ile2118Met variant in FBN1 has been reported in 1 individual with Marfan s yndrome (Comeglio 2007) and has been identified as a de novo occurrence by our l aboratory in 1 individual with Marfan syndrome. It was absent from large populat ion studies. Computational prediction tools and conservation analysis do not pro vide strong support for or against an impact to the protein. Additionally, anoth er variant affecting the same nucleotide (p.Ile2118Ile) has been shown to lead t o skipping of exon 51 (Liu 1997), suggesting changes to this nucleotide position may not be tolerated. In summary, although additional studies are required to f ully establish its clinical significance, the p.Ile2118Met variant is likely pat hogenic. -
Marfan Syndrome/Loeys-Dietz Syndrome/Familial Thoracic Aortic Aneurysms and Dissections Pathogenic:1
Variant summary: The FBN1 c.6354C>G (p.Ile2118Met) variant involves the alteration of a non-conserved nucleotide and 3/3 in silico tools predict a benign outcome for this variant (SNPsandGO and MutationTaster not captured due to low reliability index and p-value, respectively). This variant is absent in 276492 control chromosomes (publication controls and gnomAD). The variant has been reported in 1 individual with Marfan syndrome (Comeglio 2007) and described in ClinVar in a patient with Marfan syndrome as a de novo event. Another variant affecting the same nucleotide, c.6354C>T (p.Ile2118Ile - scored DV by LCA) has been reported and found to cause skipping of exon 52 (PMID: 9241263), 3/5 splicing prediction tools for the variant of interest do predict an impact on splicing. However, these predictions have not been functionally assessed. In addition, a clinical diagnostic laboratory has classified the variant as "likely pathogenic." Taken together, this variant is classified as likely pathogenic. -
Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1
This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 2118 of the FBN1 protein (p.Ile2118Met). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with Marfan syndrome (PMID: 17657824; Invitae). ClinVar contains an entry for this variant (Variation ID: 180039). 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 FBN1 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at