rs757428597

Variant names:

• chr21-43063992-C-A
• rs757428597
• NM_000071.3:c.737-1G>T

Your query was ambiguous. Multiple possible variants found:

• chr21-43063992-C-A
• chr21-43063992-C-G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1

The NM_000071.3(CBS):​c.737-1G>T variant causes a splice acceptor, intron change. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 2)
• Consequence: CBS NM_000071.3 splice_acceptor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.85
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• classic homocystinuria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, PanelApp Australia, ClinGen, Genomics England PanelApp

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.4, offset of 5, new splice context is: ttatccgtccaccatggaAGctg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CBS	NM_000071.3	c.737-1G>T		splice_acceptor_variant, intron_variant	Intron 8 of 16	ENST00000398165.8	NP_000062.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CBS	ENST00000398165.8	c.737-1G>T		splice_acceptor_variant, intron_variant	Intron 8 of 16	1	NM_000071.3	ENSP00000381231.4

Frequencies

GnomAD3 genomes Cov.: 2

GnomAD2 exomes AF: 0.00 AC: 0 AN: 241320 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS 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.: 2

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	31
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0	.;.;.;.
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.74
LIST_S2	Benign	0.0	.;.;.;.
MetaRNN	Benign	0.0	.;.;.;.
MutationAssessor	Benign	0.0	.;.;.;.
PhyloP100		6.8
PROVEAN	Benign	0.0	.;.;.;.
Sift	Pathogenic	0.0	.;.;.;.
Sift4G	Pathogenic	0.0	.;.;.;.
Vest4		0.0
GERP RS		3.9
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.87
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.25		Position offset: 31
DS_AL_spliceai		0.96		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs757428597; hg19: chr21-44484102;