rs1057516645

chr21-43058871-T-A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_000071.3(CBS):c.1321A>T(p.Lys441Ter) variant causes a stop gained change. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. K441K) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 0)
• Consequence: CBS NM_000071.3 stop_gained
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.82

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 Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 21-43058871-T-A is Pathogenic according to our data. Variant chr21-43058871-T-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 370634.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr21-43058871-T-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CBS	NM_000071.3	c.1321A>T	p.Lys441Ter	stop_gained	14/17	ENST00000398165.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CBS	ENST00000398165.8	c.1321A>T	p.Lys441Ter	stop_gained	14/17	1	NM_000071.3	P1

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Classic homocystinuria Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Mar 14, 2016

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
Cadd	Pathogenic	39
Dann	Uncertain	1.0
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.90	D
MutationTaster	Benign	1.0	A;A;A;A;A;A;A;A;A;A;A;A
Vest4		0.96
ClinPred		1.0	D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs1057516645; hg19: chr21-44478981;