chr21-43068521-T-G

Variant names:

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 2P and 12B. PM5BP4_StrongBP6_Very_Strong

The NM_000071.3(CBS):c.304A>C(p.Lys102Gln) variant causes a missense change. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K102N) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.013 ( 21 hom., cov: 6)

Exomes 𝑓: 0.0016 ( 12 hom. )

Failed GnomAD Quality Control

Consequence

CBS
NM_000071.3 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:16

Conservation

PhyloP100: 4.08

Variant links:

Genes affected

CBS (HGNC:1550): (cystathionine beta-synthase) The protein encoded by this gene acts as a homotetramer to catalyze the conversion of homocysteine to cystathionine, the first step in the transsulfuration pathway. The encoded protein is allosterically activated by adenosyl-methionine and uses pyridoxal phosphate as a cofactor. Defects in this gene can cause cystathionine beta-synthase deficiency (CBSD), which can lead to homocystinuria. This gene is a major contributor to cellular hydrogen sulfide production. Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Feb 2016]

CBS links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -10 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr21-43068519-C-G is described in Lovd as [Pathogenic].

BP4

Computational evidence support a benign effect (MetaRNN=0.012555659).

BP6

Variant 21-43068521-T-G is Benign according to our data. Variant chr21-43068521-T-G is described in ClinVar as [Likely_benign]. Clinvar id is 136677.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr21-43068521-T-G is described in Lovd as [Likely_benign]. Variant chr21-43068521-T-G is described in Lovd as [Benign]. Variant chr21-43068521-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3 link	c.304A>C	p.Lys102Gln	missense_variant	Exon 4 of 17	ENST00000398165.8	NP_000062.1	P35520-1Q9NTF0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CBS	ENST00000398165.8 link	c.304A>C	p.Lys102Gln	missense_variant	Exon 4 of 17	1	NM_000071.3	ENSP00000381231.4		P35520-1

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

514

AN:

39218

Hom.:

Cov.:

FAILED QC

Gnomad AFR

AF:

0.0590

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00361

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:

0.000217

Gnomad OTH

AF:

0.0158

GnomAD3 exomes

AF:

0.00294

AC:

740

AN:

251336

Hom.:

AF XY:

0.00200

AC XY:

272

AN XY:

135872

show subpopulations

Gnomad AFR exome

AF:

0.0398

Gnomad AMR exome

AF:

0.00202

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000150

Gnomad OTH exome

AF:

0.00114

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00160

AC:

522

AN:

326162

Hom.:

Cov.:

AF XY:

0.00125

AC XY:

219

AN XY:

175858

show subpopulations

Gnomad4 AFR exome

AF:

0.0450

Gnomad4 AMR exome

AF:

0.00230

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000472

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000158

Gnomad4 OTH exome

AF:

0.00300

GnomAD4 genome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.0131

AC:

514

AN:

39308

Hom.:

Cov.:

AF XY:

0.0123

AC XY:

221

AN XY:

18028

show subpopulations

Gnomad4 AFR

AF:

0.0585

Gnomad4 AMR

AF:

0.00359

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000217

Gnomad4 OTH

AF:

0.0154

Alfa

AF:

0.00181

Hom.:

ESP6500AA

AF:

0.0379

AC:

167

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00362

AC:

440

Asia WGS

AF:

0.00289

AC:

AN:

3478

EpiCase

AF:

0.000109

EpiControl

AF:

0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:16

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:5

Jul 16, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Lys102Gln in exon 4 of CBS: This variant is not expected to have clinical sign ificance because it has been identified in 4% (415/10368) of African chromosomes by the Exome Aggregation Consortium (ExAC,http://exac.broadinstitute.org; dbSNP rs34040148). -

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

May 17, 2022

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CBS c.304A>C (p.Lys102Gln) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0029 in 251336 control chromosomes, predominantly at a frequency of 0.04 within the African or African-American subpopulation in the gnomAD database, including 15 homozygotes. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 13 fold of the estimated maximal expected allele frequency for a pathogenic variant in CBS causing Homocystinuria phenotype (0.003), 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.304A>C in individuals affected with Homocystinuria and no experimental evidence demonstrating its impact on protein function have been reported. Ten clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -

Feb 03, 2015

Eurofins Ntd Llc (ga)

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Benign:5

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

May 21, 2015

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 28, 2018

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 22267502, 20981092, 21228398, 10338090) -

Sep 21, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Breakthrough Genomics, Breakthrough Genomics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Classic homocystinuria

Benign:3

Sep 16, 2020

Natera, Inc.

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

May 31, 2018

SIB Swiss Institute of Bioinformatics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: curation

This variant is interpreted as a Benign, for Homocystinuria due to cystathionine beta-synthase deficiency, in Autosomal Recessive manner. The following ACMG Tag(s) were applied: BS1 => Allele frequency is greater than expected for disorder. BS2 => Observed in a healthy adult individual for a recessive (homozygous), dominant (heterozygous), or X-linked (hemizygous) disorder, with full penetrance expected at an early age. BP4 => Multiple lines of computational evidence suggest no impact on gene or gene product (conservation, evolutionary, splicing impact, etc.). -

Familial thoracic aortic aneurysm and aortic dissection

Benign:1

Aug 25, 2015

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. -

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED

Benign:1

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Connective tissue disorder

Benign:1

Mar 01, 2019

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Uncertain

-0.030

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Pathogenic

0.93

D;D;D;D;.

Eigen

Benign

0.16

Eigen_PC

Benign

0.20

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.91

.;.;.;D;D

MetaRNN

Benign

0.013

T;T;T;T;T

MetaSVM

Uncertain

0.063

MutationAssessor

Benign

1.9

L;L;L;L;.

PrimateAI

Uncertain

0.66

PROVEAN

Benign

-2.3

N;N;N;N;D

REVEL

Uncertain

0.58

Sift

Benign

0.10

T;T;T;T;T

Sift4G

Benign

0.091

T;T;T;T;T

Polyphen

0.56

P;P;P;P;.

Vest4

0.49

MVP

0.85

MPC

0.39

ClinPred

0.024

GERP RS

4.8

Varity_R

0.64

gMVP

0.80

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over