chr21-43062954-G-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP2

The NM_000071.3(CBS):c.953C>T(p.Thr318Met) variant causes a missense, splice region change. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T318T) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 0)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CBS
NM_000071.3 missense, splice_region

Scores

Splicing: ADA: 0.001946

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 3.81

Publications

0 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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_000071.3

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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3 link	c.953C>T	p.Thr318Met	missense_variant, splice_region_variant	Exon 10 of 17	ENST00000398165.8	NP_000062.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CBS	ENST00000398165.8 link	c.953C>T	p.Thr318Met	missense_variant, splice_region_variant	Exon 10 of 17	1	NM_000071.3	ENSP00000381231.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.0000518

AC:

AN:

251150

AF XY:

0.0000295

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.000202

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

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

AF:

0.00

AC:

AN:

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

African (AFR)

AF:

0.00

AC:

AN:

American (AMR)

AC:

AN:

Ashkenazi Jewish (ASJ)

AC:

AN:

East Asian (EAS)

AC:

AN:

South Asian (SAS)

AC:

AN:

European-Finnish (FIN)

AC:

AN:

Middle Eastern (MID)

AC:

AN:

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

Other (OTH)

AF:

0.00

AC:

AN:

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000445

Hom.:

ExAC

AF:

0.0000576

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Classic homocystinuria

Uncertain:2

Jan 24, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Apr 12, 2018

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

not provided

Uncertain:2

Sep 10, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 28472652) -

Jun 29, 2018

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The CBS c.953C>T; p.Thr318Met variant (rs769541394), to our knowledge, is not reported in the medical literature in association with a CBS related disorder, but it is reported as a variant of uncertain significance in ClinVar (Variation ID: 405378). This variant is found in the general population with an overall allele frequency of 0.0045% (11/245,976 alleles) in the Genome Aggregation Database. The threonine at codon 318 is weakly conserved, but computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. Due to limited information, the clinical significance of the c.953C>T variant is uncertain at this time. -

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED

Uncertain:1

Jul 03, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 318 of the CBS protein (p.Thr318Met). This variant is present in population databases (rs769541394, gnomAD 0.02%). 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: 405378). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). 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

0.076

BayesDel_addAF

Benign

-0.088

BayesDel_noAF

Benign

-0.090

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.96

D;D;D;D

Eigen

Benign

0.13

Eigen_PC

Benign

-0.019

FATHMM_MKL

Uncertain

0.85

LIST_S2

Uncertain

0.97

.;.;.;D

M_CAP

Pathogenic

0.39

MetaRNN

Uncertain

0.65

D;D;D;D

MetaSVM

Uncertain

0.57

MutationAssessor

Uncertain

2.6

M;M;M;M

PhyloP100

3.8

PrimateAI

Benign

0.38

PROVEAN

Benign

-2.3

N;N;N;N

REVEL

Uncertain

0.42

Sift

Uncertain

0.0070

D;D;D;D

Sift4G

Uncertain

0.011

D;D;D;D

Polyphen

1.0

D;D;D;D

Vest4

0.31

MutPred

0.46

Loss of phosphorylation at T318 (P = 0.0217);Loss of phosphorylation at T318 (P = 0.0217);Loss of phosphorylation at T318 (P = 0.0217);Loss of phosphorylation at T318 (P = 0.0217);

MVP

0.90

MPC

0.41

ClinPred

0.33

GERP RS

-0.18

Varity_R

0.15

gMVP

0.47

Mutation Taster

=71/29

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.0019

dbscSNV1_RF

Benign

0.23

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

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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