rs144832032

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1PM5BP4_Moderate

The NM_000071.3(CBS):c.404C>T(p.Thr135Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000346 in 1,097,702 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. 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. T135?) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000080 ( 1 hom., cov: 14)

Exomes 𝑓: 0.000030 ( 1 hom. )

Consequence

CBS
NM_000071.3 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.19

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 Uncertain_significance. Variant got 2 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, 10 uncertain in NM_000071.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr21-43066290-GT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 558326.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP4

Computational evidence support a benign effect (MetaRNN=0.17937884).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CBS	NM_000071.3 linkuse as main transcript	c.404C>T	p.Thr135Met	missense_variant	5/17	ENST00000398165.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CBS	ENST00000398165.8 linkuse as main transcript	c.404C>T	p.Thr135Met	missense_variant	5/17	1	NM_000071.3	P1	P35520-1

Frequencies

GnomAD3 genomes

AF:

0.0000801

AC:

AN:

99908

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000287

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000869

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:

0.0000395

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000439

AC:

AN:

250664

Hom.:

AF XY:

0.0000369

AC XY:

AN XY:

135632

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000617

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000301

AC:

AN:

997794

Hom.:

Cov.:

AF XY:

0.0000295

AC XY:

AN XY:

508924

show subpopulations

Gnomad4 AFR exome

AF:

0.0000607

Gnomad4 AMR exome

AF:

0.0000713

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000801

AC:

AN:

99908

Hom.:

Cov.:

AF XY:

0.0000620

AC XY:

AN XY:

48364

show subpopulations

Gnomad4 AFR

AF:

0.000287

Gnomad4 AMR

AF:

0.0000869

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000395

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000706

Hom.:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.00

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

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 15, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 08, 2022	- -

Familial thoracic aortic aneurysm and aortic dissection

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 18, 2023

The p.T135M variant (also known as c.404C>T), located in coding exon 3 of the CBS gene, results from a C to T substitution at nucleotide position 404. The threonine at codon 135 is replaced by methionine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

HYPERHOMOCYSTEINEMIA, THROMBOTIC, CBS-RELATED

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 08, 2022

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 135 of the CBS protein (p.Thr135Met). This variant is present in population databases (rs144832032, gnomAD 0.007%). 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: 471364). 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 CBS 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Mayo Clinic Laboratories, Mayo Clinic

Sep 26, 2022

BP4 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.070

BayesDel_addAF

Benign

-0.085

BayesDel_noAF

Benign

-0.18

Cadd

Benign

Dann

Uncertain

0.99

DEOGEN2

Uncertain

0.67

D;D;D;D;.

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.060

M_CAP

Uncertain

0.20

MetaRNN

Benign

0.18

T;T;T;T;T

MetaSVM

Uncertain

0.70

MutationAssessor

Benign

0.88

L;L;L;L;.

MutationTaster

Benign

1.0

N;N;N;N;N;N;N;N;N;N;N;N

PrimateAI

Benign

0.38

PROVEAN

Benign

0.54

N;N;N;N;N

REVEL

Benign

0.22

Sift

Benign

0.24

T;T;T;T;T

Sift4G

Benign

0.24

T;T;T;T;T

Polyphen

0.036

B;B;B;B;.

Vest4

0.37

MVP

0.54

MPC

0.38

ClinPred

0.035

GERP RS

-0.95

Varity_R

0.063

gMVP

0.45

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