21-43058935-C-T

Variant names:

• chr21-43058935-C-T
• rs138432416
• NM_000071.3:c.1257G>A

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Strong BP6 BP7

The NM_000071.3(CBS):​c.1257G>A​(p.Leu419Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 0)
• Consequence: CBS NM_000071.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:6
• Conservation: PhyloP100: 0.816

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]

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.52).
• BP6: Variant 21-43058935-C-T is Benign according to our data. Variant chr21-43058935-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 194318.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Benign=3, Uncertain_significance=1}.
• BP7: Synonymous conserved (PhyloP=0.816 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3	c.1257G>A	p.Leu419Leu	synonymous_variant	Exon 14 of 17	ENST00000398165.8	NP_000062.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CBS	ENST00000398165.8	c.1257G>A	p.Leu419Leu	synonymous_variant	Exon 14 of 17	1	NM_000071.3	ENSP00000381231.4

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD3 exomes AF: 0.000219 AC: 44 AN: 200618 Hom.: 0 AF XY: 0.000139 AC XY: 15 AN XY: 108008

Gnomad AFR exome AF: 0.00351

Gnomad AMR exome AF: 0.0000685

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 0

Alfa AF: 0.00115 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:6

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Benign:3

Feb 17, 2015

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 13, 2014

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Aug 10, 2023

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Connective tissue disorder Uncertain:1

Feb 01, 2019

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial thoracic aortic aneurysm and aortic dissection Benign:1

Mar 05, 2020

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely 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 24, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:1

Nov 07, 2019

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.52
CADD	Benign	9.1
DANN	Benign	0.52

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

Other links and lift over

dbSNP: rs138432416; hg19: chr21-44479045;