rs25397

Variant names:

• chr15-48644691-C-T
• rs25397
• NM_000138.5:c.79G>A

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BA1 BP4

This summary comes from the ClinGen Evidence Repository: The NM_000138.5 c.79G>A, is a missense variant in FBN1 predicted to cause a substitution of a alanine acid by threonine at amino acid 27 (p.Ala27Thr). This variant has been previously reported in ClinVar as likely benign and benign (Variation ID: 163486). This variant has been identified in 129/19954 (0.65%) of individuals of East Asian origin (MAF: 0.65%) (BA1; https://gnomad.broadinstitute.org/ version 2.1.1). It has been reported in individuals with thoracic aortic aneurysm and/or dissection, and in individuals with clinical features of Marfan syndrome, however it was considered to be a polymorphism (PMID 26272055, 19839986, 16835936). Computational prediction tools and conservation analysis suggests no impact on the protein (REVEL: 0.097) (BP4). The constraint z-score for missense variants affecting FBN1 is 5.06, however due to the presence of two benign arguments, PP2 cannot be used. In summary, this variant meets criteria to be classified as benign for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGenFBN1 VCEP: BA1, BP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA017499/MONDO:0007947/022

• Frequency:
  • Genomes: 𝑓 0.00026 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00016 (1 hom.)
• Consequence: FBN1 NM_000138.5 missense
• Clinical Significance: Benign reviewed by expert panel B:18
• Conservation: PhyloP100: -0.0340
• Publications: 13 publications found

Genes affected

FBN1 (HGNC:3603): (fibrillin 1) This gene encodes a member of the fibrillin family of proteins. The encoded preproprotein is proteolytically processed to generate two proteins including the extracellular matrix component fibrillin-1 and the protein hormone asprosin. Fibrillin-1 is an extracellular matrix glycoprotein that serves as a structural component of calcium-binding microfibrils. These microfibrils provide force-bearing structural support in elastic and nonelastic connective tissue throughout the body. Asprosin, secreted by white adipose tissue, has been shown to regulate glucose homeostasis. Mutations in this gene are associated with Marfan syndrome and the related MASS phenotype, as well as ectopia lentis syndrome, Weill-Marchesani syndrome, Shprintzen-Goldberg syndrome and neonatal progeroid syndrome. [provided by RefSeq, Apr 2016]

FBN1 Gene-Disease associations (from GenCC):

• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Marfan syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P, PanelApp Australia, Orphanet, Ambry Genetics
• Acromicric dysplasia

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics
• progeroid and marfanoid aspect-lipodystrophy syndrome

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• stiff skin syndrome

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• Weill-Marchesani syndrome 2, dominant

  Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• geleophysic dysplasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• isolated ectopia lentis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• neonatal Marfan syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Weill-Marchesani syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• ectopia lentis 1, isolated, autosomal dominant

  Inheritance: AD Classification: LIMITED Submitted by: G2P
• Shprintzen-Goldberg syndrome

  Inheritance: AD, Unknown Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Benign. The variant received -9 ACMG points.

• BP4: For more information check the summary or visit ClinGen Evidence Repository.
• BA1: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FBN1	NM_000138.5	c.79G>A	p.Ala27Thr	missense_variant	Exon 2 of 66	ENST00000316623.10	NP_000129.3
FBN1	NM_001406716.1	c.79G>A	p.Ala27Thr	missense_variant	Exon 1 of 65		NP_001393645.1
FBN1	NM_001406717.1	c.79G>A	p.Ala27Thr	missense_variant	Exon 2 of 9		NP_001393646.1
FBN1	NM_001406718.1	c.79G>A	p.Ala27Thr	missense_variant	Exon 2 of 3		NP_001393647.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FBN1	ENST00000316623.10	c.79G>A	p.Ala27Thr	missense_variant	Exon 2 of 66	1	NM_000138.5	ENSP00000325527.5

Frequencies

GnomAD3 genomes AF: 0.000256 AC: 39 AN: 152206 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00734

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

GnomAD2 exomes AF: 0.000477 AC: 120 AN: 251470 AF XY: 0.000427

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00631

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.000489

GnomAD4 exome AF: 0.000159 AC: 232 AN: 1461862 Hom.: 1 Cov.: 30 AF XY: 0.000158 AC XY: 115 AN XY: 727228

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00544 AC: 216 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1112010

Other (OTH) AF: 0.000116 AC: 7 AN: 60396

GnomAD4 genome AF: 0.000256 AC: 39 AN: 152324 Hom.: 1 Cov.: 33 AF XY: 0.000269 AC XY: 20 AN XY: 74482

African (AFR) AF: 0.00 AC: 0 AN: 41588

American (AMR) AF: 0.00 AC: 0 AN: 15314

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00736 AC: 38 AN: 5164

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68010

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.000214 Hom.: 2

Bravo AF: 0.000332

ExAC AF: 0.000436 AC: 53

Asia WGS AF: 0.00289 AC: 10 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:18

Revision: reviewed by expert panel

Submissions by phenotype

not provided Benign:5

Sep 23, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 26272055, 19839986, 16835936)

Jul 20, 2017

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The FBN1 c.79G>A (p.Ala27Thr) variant involves the alteration of a non-conserved nucleotide and 3/4 in silico tools (SNPsandGO not captured due to low reliability index) predict a benign outcome. However, these predictions have yet to be functionally assessed. This variant was found in 60/124386 control chromosomes, predominantly observed in the East Asian cohort at a frequency of 0.00601 (52/8652). This frequency is about 53 times the estimated maximal expected allele frequency of a pathogenic FBN1 variant (0.0001125), suggesting this is likely a benign polymorphism found primarily in population(s) of East Asia. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as likely benign/benign. Taken together, this variant is classified as benign.

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

Marfan syndrome Benign:3

Sep 17, 2024

All of Us Research Program, National Institutes of Health

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Sep 28, 2023

ClinGen FBN1 Variant Curation Expert Panel, ClinGen

Significance: Benign

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000138.5 c.79G>A, is a missense variant in FBN1 predicted to cause a substitution of a alanine acid by threonine at amino acid 27 (p.Ala27Thr). This variant has been previously reported in ClinVar as likely benign and benign (Variation ID: 163486). This variant has been identified in 129/19954 (0.65%) of individuals of East Asian origin (MAF: 0.65%) (BA1; https://gnomad.broadinstitute.org/ version 2.1.1). It has been reported in individuals with thoracic aortic aneurysm and/or dissection, and in individuals with clinical features of Marfan syndrome, however it was considered to be a polymorphism (PMID 26272055, 19839986, 16835936). Computational prediction tools and conservation analysis suggests no impact on the protein (REVEL: 0.097) (BP4). The constraint z-score for missense variants affecting FBN1 is 5.06, however due to the presence of two benign arguments, PP2 cannot be used. In summary, this variant meets criteria to be classified as benign for Marfan syndrome based on the ACMG/AMP criteria applied, as specified by the ClinGenFBN1 VCEP: BA1, BP4.

Familial thoracic aortic aneurysm and aortic dissection Benign:3

Apr 14, 2018

Color Diagnostics, LLC DBA Color Health

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Sep 16, 2019

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease.

not specified Benign:1

Oct 12, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Ala27Thr in exon 1 of FBN1: This variant is not expected to have clinical sign ificance because it has been identified in 0.6% (52/8652) of East Asian chromoso mes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; d bSNP rs25397).

Stiff skin syndrome Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Weill-Marchesani syndrome Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Geleophysic dysplasia Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Acromicric dysplasia Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Marfan syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Benign:1

Dec 11, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Ectopia lentis 1, isolated, autosomal dominant Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.063
BayesDel_addAF	Benign	-0.46	T
BayesDel_noAF	Benign	-0.42
CADD	Benign	13
DANN	Benign	0.95
DEOGEN2	Benign	0.0	.;T
Eigen	Benign	-0.95
Eigen_PC	Benign	-0.89
FATHMM_MKL	Benign	0.071	N
LIST_S2	Benign	0.65	T;T
M_CAP	Uncertain	0.18	D
MetaRNN	Benign	0.0046	T;T
MetaSVM	Benign	-0.80	T
MutationAssessor	Benign	0.0	.;.
PhyloP100		-0.034
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-0.52	N;N
REVEL	Benign	0.097
Sift	Benign	0.46	T;T
Sift4G	Benign	0.088	T;T
Vest4		0.038
ClinPred		0.019	T
GERP RS		0.32
Mutation Taster		=93/7	polymorphism

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

Other links and lift over

dbSNP: rs25397; hg19: chr15-48936888;