5-128366419-C-G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001999.4(FBN2):​c.2260G>C​(p.Gly754Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000187 in 1,603,218 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G754S) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

FBN2
NM_001999.4 missense

Scores

2
9
8

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.59

Publications

10 publications found
Variant links:
Genes affected
FBN2 (HGNC:3604): (fibrillin 2) The protein encoded by this gene is a component of connective tissue microfibrils and may be involved in elastic fiber assembly. Mutations in this gene cause congenital contractural arachnodactyly. [provided by RefSeq, Jul 2008]
FBN2 Gene-Disease associations (from GenCC):
  • congenital contractural arachnodactyly
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
  • carpal tunnel syndrome
    Inheritance: AD Classification: LIMITED Submitted by: Franklin by Genoox
  • familial thoracic aortic aneurysm and aortic dissection
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen
  • macular degeneration, early-onset
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
FBN2NM_001999.4 linkc.2260G>C p.Gly754Arg missense_variant Exon 17 of 65 ENST00000262464.9 NP_001990.2 P35556-1
FBN2XM_017009228.3 linkc.2107G>C p.Gly703Arg missense_variant Exon 16 of 64 XP_016864717.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
FBN2ENST00000262464.9 linkc.2260G>C p.Gly754Arg missense_variant Exon 17 of 65 1 NM_001999.4 ENSP00000262464.4 P35556-1
FBN2ENST00000508989.5 linkc.2161G>C p.Gly721Arg missense_variant Exon 16 of 33 2 ENSP00000425596.1 D6RJI3
FBN2ENST00000511489.1 linkn.481G>C non_coding_transcript_exon_variant Exon 5 of 6 3

Frequencies

GnomAD3 genomes
AF:
0.00000658
AC:
1
AN:
151968
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000138
AC:
2
AN:
1451250
Hom.:
0
Cov.:
26
AF XY:
0.00000138
AC XY:
1
AN XY:
722434
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33276
American (AMR)
AF:
0.00
AC:
0
AN:
44468
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25968
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39366
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85618
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53134
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5730
European-Non Finnish (NFE)
AF:
9.06e-7
AC:
1
AN:
1103724
Other (OTH)
AF:
0.0000167
AC:
1
AN:
59966
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0385499), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000658
AC:
1
AN:
151968
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74202
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41406
American (AMR)
AF:
0.00
AC:
0
AN:
15242
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5192
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4808
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10568
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67968
Other (OTH)
AF:
0.00
AC:
0
AN:
2088
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Congenital contractural arachnodactyly Uncertain:1
Nov 01, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant has not been reported in the literature in individuals affected with FBN2-related conditions. This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 754 of the FBN2 protein (p.Gly754Arg). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 840658). 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 FBN2 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.20
BayesDel_addAF
Pathogenic
0.22
D
BayesDel_noAF
Uncertain
0.080
CADD
Benign
22
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.44
T;.;T;T
Eigen
Benign
0.061
Eigen_PC
Benign
0.062
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.93
D;.;.;D
M_CAP
Uncertain
0.23
D
MetaRNN
Uncertain
0.58
D;D;D;D
MetaSVM
Uncertain
0.53
D
MutationAssessor
Benign
0.38
N;.;N;.
PhyloP100
4.6
PrimateAI
Uncertain
0.62
T
PROVEAN
Benign
-1.6
N;.;N;N
REVEL
Pathogenic
0.75
Sift
Benign
0.035
D;.;D;D
Sift4G
Benign
0.18
.;.;.;T
Polyphen
1.0
D;.;D;D
Vest4
0.53
MutPred
0.78
Loss of catalytic residue at C756 (P = 0.1253);.;Loss of catalytic residue at C756 (P = 0.1253);.;
MVP
0.80
MPC
0.36
ClinPred
0.70
D
GERP RS
3.9
Varity_R
0.12
gMVP
0.85
Mutation Taster
=63/37
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.010
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs145259927; hg19: chr5-127702112; API