21-43066243-C-A

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1PM5PP2PP3_Strong

The NM_000071.3(CBS):c.451G>T(p.Gly151Trp) variant causes a missense, splice region change. In-silico tool predicts a pathogenic outcome for this variant. 14/24 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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. G151R) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 16)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CBS
NM_000071.3 missense, splice_region

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.84

Publications

10 publications found

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 Gene-Disease associations (from GenCC):

classic homocystinuria
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, PanelApp Australia, ClinGen, Genomics England PanelApp

CBS links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

PM1

In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 1 uncertain in NM_000071.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr21-43066243-C-T is described in CliVar as Pathogenic. Clinvar id is 863694.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 107 curated pathogenic missense variants (we use a threshold of 10). The gene has 4 curated benign missense variants. Gene score misZ: 0.8318 (below the threshold of 3.09). Trascript score misZ: NaN (below the threshold of 3.09). GenCC associations: The gene is linked to classic homocystinuria.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3 link	c.451G>T	p.Gly151Trp	missense_variant, splice_region_variant	Exon 5 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.451G>T	p.Gly151Trp	missense_variant, splice_region_variant	Exon 5 of 17	1	NM_000071.3	ENSP00000381231.4		P35520-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000402

AC:

AN:

248820

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000619

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AC0;AS_VQSR

AF:

0.00

AC:

AN:

1234290

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

616944

African (AFR)

AF:

0.00

AC:

AN:

18558

American (AMR)

AF:

0.00

AC:

AN:

42294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

21990

East Asian (EAS)

AF:

0.00

AC:

AN:

38862

South Asian (SAS)

AF:

0.00

AC:

AN:

76528

European-Finnish (FIN)

AF:

0.00

AC:

AN:

40386

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4432

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

939638

Other (OTH)

AF:

0.00

AC:

AN:

51602

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED

Uncertain:1

Feb 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with tryptophan, which is neutral and slightly polar, at codon 151 of the CBS protein (p.Gly151Trp). This variant also falls at the last nucleotide of exon 5, which is part of the consensus splice site for this exon. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with CBS-related conditions. ClinVar contains an entry for this variant (Variation ID: 582499). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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 may disrupt the consensus splice site. 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

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.40

BayesDel_noAF

Pathogenic

0.57

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.99

D;D;D;D;.

Eigen

Pathogenic

0.90

Eigen_PC

Pathogenic

0.72

FATHMM_MKL

Uncertain

0.90

LIST_S2

Pathogenic

1.0

.;.;.;D;D

M_CAP

Pathogenic

0.92

MetaRNN

Pathogenic

0.99

D;D;D;D;D

MetaSVM

Pathogenic

0.91

MutationAssessor

Pathogenic

4.8

H;H;H;H;.

PhyloP100

6.8

PrimateAI

Pathogenic

0.86

PROVEAN

Pathogenic

-8.0

D;D;D;D;D

REVEL

Pathogenic

0.96

Sift

Pathogenic

0.0

D;D;D;D;D

Sift4G

Pathogenic

0.0

D;D;D;D;D

Polyphen

1.0

D;D;D;D;.

Vest4

0.99

MutPred

0.96

Loss of disorder (P = 0.0524);Loss of disorder (P = 0.0524);Loss of disorder (P = 0.0524);Loss of disorder (P = 0.0524);Loss of disorder (P = 0.0524);

MVP

0.93

MPC

1.2

ClinPred

1.0

GERP RS

5.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.98

gMVP

0.99

Mutation Taster

=1/99

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.050

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over