rs1555872506

chr21-43058891-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PP3_Strong

The NM_000071.3(CBS):c.1301C>A(p.Thr434Asn) variant causes a missense change involving the alteration of a conserved nucleotide. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 0)
• Consequence: CBS NM_000071.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.48

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_pathogenic. Variant got 6 ACMG points.

• PM1: In a domain CBS (size 58) in uniprot entity CBS_HUMAN there are 17 pathogenic changes around while only 1 benign (94%) in NM_000071.3
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CBS	NM_000071.3	c.1301C>A	p.Thr434Asn	missense_variant	14/17	ENST00000398165.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CBS	ENST00000398165.8	c.1301C>A	p.Thr434Asn	missense_variant	14/17	1	NM_000071.3	P1

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 0

Alfa AF: 0.0000472 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Classic homocystinuria Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

May 12, 2017

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.62
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.96	D;D;D;D
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.1	M;M;M;M
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-2.6	D;D;D;D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D;D;D;D
Sift4G	Uncertain	0.0060	D;D;D;D
Polyphen		0.86	P;P;P;P
Vest4		0.93
MutPred		0.83		Gain of glycosylation at T430 (P = 0.1486);Gain of glycosylation at T430 (P = 0.1486);Gain of glycosylation at T430 (P = 0.1486);Gain of glycosylation at T430 (P = 0.1486);
MVP		0.88
MPC		0.80
ClinPred		0.98	D
GERP RS		4.7
Varity_R		0.95
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1555872506; hg19: chr21-44479001;