1-70429791-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001902.6(CTH):c.589-3C>T variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000509 in 1,610,106 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000051 (0 hom.)
• Consequence: CTH NM_001902.6 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.0006451
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.410

Genes affected

CTH (HGNC:2501): (cystathionine gamma-lyase) This gene encodes a cytoplasmic enzyme in the trans-sulfuration pathway that converts cystathione derived from methionine into cysteine. Glutathione synthesis in the liver is dependent upon the availability of cysteine. Mutations in this gene cause cystathioninuria. Alternative splicing of this gene results in three transcript variants encoding different isoforms. [provided by RefSeq, Jun 2010]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.56).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTH	NM_001902.6	c.589-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000370938.8
CTH	NM_001190463.2	c.493-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant
CTH	NM_153742.5	c.457-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant
CTH	XM_017000416.3	c.19-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTH	ENST00000370938.8	c.589-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_001902.6	P1
CTH	ENST00000346806.2	c.457-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1
CTH	ENST00000411986.6	c.493-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		2
CTH	ENST00000464926.1	n.637-3C>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes AF: 0.0000526 AC: 8 AN: 152182 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.000577

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000882

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000104 AC: 26 AN: 250842 Hom.: 0 AF XY: 0.000111 AC XY: 15 AN XY: 135552

Gnomad AFR exome AF: 0.0000616

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00179

Gnomad EAS exome AF: 0.000163

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000508 AC: 74 AN: 1457924 Hom.: 0 Cov.: 29 AF XY: 0.0000524 AC XY: 38 AN XY: 725446

Gnomad4 AFR exome AF: 0.0000599

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.000959

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000334

Gnomad4 OTH exome AF: 0.000149

GnomAD4 genome AF: 0.0000526 AC: 8 AN: 152182 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74338

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.000577

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000882

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000115 Hom.: 0

Bravo AF: 0.0000453

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cystathioninuria Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.56
Cadd	Benign	8.4
Dann	Benign	0.47
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00065
dbscSNV1_RF	Benign	0.024
SpliceAI score (max)		0.11		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: rs201568449; hg19: chr1-70895474;