21-43058973-G-C

Variant names:

• chr21-43058973-G-C
• rs370071493
• NM_000071.3:c.1224-5C>G

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_000071.3(CBS):​c.1224-5C>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 0)
• Consequence: CBS NM_000071.3 splice_region, intron
• Scores: Splicing: ADA: 0.0006706
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.151
• 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: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet, Myriad Women’s Health, Genomics England PanelApp

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000071.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CBS	NM_000071.3	MANE Select	c.1224-5C>G		splice_region intron	N/A	NP_000062.1	P35520-1
	CBS	NM_001178008.3		c.1224-5C>G		splice_region intron	N/A	NP_001171479.1	P35520-1
	CBS	NM_001178009.3		c.1224-5C>G		splice_region intron	N/A	NP_001171480.1	P35520-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CBS	ENST00000398165.8	TSL:1 MANE Select	c.1224-5C>G		splice_region intron	N/A	ENSP00000381231.4	P35520-1
	CBS	ENST00000352178.9	TSL:1	c.1224-5C>G		splice_region intron	N/A	ENSP00000344460.5	P35520-1
	CBS	ENST00000359624.7	TSL:1	c.1224-5C>G		splice_region intron	N/A	ENSP00000352643.3	P35520-1

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD2 exomes AF: 0.00000461 AC: 1 AN: 216712 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: 0.0000683

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	12
DANN	Benign	0.62
PhyloP100		-0.15
PromoterAI		0.065	Neutral

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00067
dbscSNV1_RF	Benign	0.062
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

Other links and lift over

dbSNP: rs370071493; hg19: chr21-44479083;