chr21-43063931-C-G

Variant names:

• chr21-43063931-C-G
• NM_000071.3:c.797G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM5 PP3_Strong

The NM_000071.3(CBS):​c.797G>C​(p.Arg266Thr) variant causes a missense change. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R266G) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 4)
• Consequence: CBS NM_000071.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.85

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 8 ACMG points.

• PM1: In a helix (size 12) in uniprot entity CBS_HUMAN there are 9 pathogenic changes around while only 0 benign (100%) in NM_000071.3
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.973

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3	c.797G>C	p.Arg266Thr	missense_variant	Exon 9 of 17	ENST00000398165.8	NP_000062.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CBS	ENST00000398165.8	c.797G>C	p.Arg266Thr	missense_variant	Exon 9 of 17	1	NM_000071.3	ENSP00000381231.4

Frequencies

GnomAD3 genomes Cov.: 4

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 4

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	28
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.98	D;D;D;D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	.;.;.;D
M_CAP	Pathogenic	0.60	D
MetaRNN	Pathogenic	0.97	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	M;M;M;M
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-5.8	D;D;D;D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	D;D;D;D
Vest4		0.92
MutPred		0.80		Loss of MoRF binding (P = 0.0283);Loss of MoRF binding (P = 0.0283);Loss of MoRF binding (P = 0.0283);Loss of MoRF binding (P = 0.0283);
MVP		0.94
MPC		1.4
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.97
gMVP		0.96

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr21-44484041;