NM_000138.5:c.5917+3A>G
Variant summary
Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBP6
The NM_000138.5(FBN1):c.5917+3A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000236 in 1,612,576 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000138.5 splice_region, intron
Scores
Clinical Significance
Conservation
Publications
- familial thoracic aortic aneurysm and aortic dissectionInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
- Marfan syndromeInheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P, PanelApp Australia, Orphanet, Ambry Genetics
- Acromicric dysplasiaInheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics
- progeroid and marfanoid aspect-lipodystrophy syndromeInheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
- stiff skin syndromeInheritance: AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
- Weill-Marchesani syndrome 2, dominantInheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
- geleophysic dysplasiaInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- isolated ectopia lentisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- neonatal Marfan syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Weill-Marchesani syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- ectopia lentis 1, isolated, autosomal dominantInheritance: AD Classification: LIMITED Submitted by: G2P
- Shprintzen-Goldberg syndromeInheritance: AD, Unknown Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Likely_benign. The variant received -3 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| FBN1 | ENST00000316623.10 | c.5917+3A>G | splice_region_variant, intron_variant | Intron 48 of 65 | 1 | NM_000138.5 | ENSP00000325527.5 |
Frequencies
GnomAD3 genomes AF: 0.000132 AC: 20AN: 151832Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000319 AC: 8AN: 250608 AF XY: 0.0000148 show subpopulations
GnomAD4 exome AF: 0.0000123 AC: 18AN: 1460628Hom.: 0 Cov.: 31 AF XY: 0.00000826 AC XY: 6AN XY: 726628 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000132 AC: 20AN: 151948Hom.: 0 Cov.: 31 AF XY: 0.000162 AC XY: 12AN XY: 74270 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Familial thoracic aortic aneurysm and aortic dissection Uncertain:2Benign:2
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The c.5917+3A>G intronic variant results from an A to G substitution 3 nucleotides after coding exon 47 in the FBN1 gene. This nucleotide position is poorly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
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Marfan syndrome Benign:2
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not specified Benign:2
Variant summary: FBN1 c.5917+3A>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4.3e-05 in 281838 control chromosomes, predominantly at a frequency of 0.00044 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 4 fold of the estimated maximal expected allele frequency for a pathogenic variant in FBN1 causing Marfan Syndrome phenotype (0.00011), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.5917+3A>G in individuals affected with Marfan Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Two ClinVar submissions from clinical diagnostic laboratories (evaluation after 2014) cites the variant once as uncertain significance and once as likely benign. Based on the evidence outlined above, the variant was classified as benign. -
This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Uncertain:1
This sequence change falls in intron 48 of the FBN1 gene. It does not directly change the encoded amino acid sequence of the FBN1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs202158568, gnomAD 0.05%). This variant has not been reported in the literature in individuals affected with FBN1-related conditions. ClinVar contains an entry for this variant (Variation ID: 199950). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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. -
Ectopia lentis Benign:1
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Stiff skin syndrome Benign:1
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MASS syndrome Benign:1
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Weill-Marchesani syndrome Benign:1
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Geleophysic dysplasia Benign:1
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Acromicric dysplasia Benign:1
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FBN1-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at