22-19759679-T-G

Variant names:

• chr22-19759679-T-G
• rs1601280018
• ENST00000332710.8:c.34+2T>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The ENST00000332710.8(TBX1):​c.34+2T>G variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. 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: 33)
• Consequence: TBX1 ENST00000332710.8 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.27
• Publications: 0 publications found

Genes affected

TBX1 (HGNC:11592): (T-box transcription factor 1) This gene is a member of a phylogenetically conserved family of genes that share a common DNA-binding domain, the T-box. T-box genes encode transcription factors involved in the regulation of developmental processes. This gene product shares 98% amino acid sequence identity with the mouse ortholog. DiGeorge syndrome (DGS)/velocardiofacial syndrome (VCFS), a common congenital disorder characterized by neural-crest-related developmental defects, has been associated with deletions of chromosome 22q11.2, where this gene has been mapped. Studies using mouse models of DiGeorge syndrome suggest a major role for this gene in the molecular etiology of DGS/VCFS. Several alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2008]

TBX1 Gene-Disease associations (from GenCC):

• conotruncal heart malformations

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• DiGeorge syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• velocardiofacial syndrome

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• 22q11.2 deletion syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.08064516 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TBX1	NM_080647.1	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 8		NP_542378.1
TBX1	NM_080646.2	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 8		NP_542377.1
TBX1	NM_005992.1	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 9		NP_005983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TBX1	ENST00000332710.8	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 8	1		ENSP00000331791.4
TBX1	ENST00000329705.11	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 8	1		ENSP00000331176.7
TBX1	ENST00000359500.7	c.34+2T>G		splice_donor_variant, intron_variant	Intron 2 of 9	1		ENSP00000352483.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Uncertain	0.080
CADD	Benign	22
DANN	Uncertain	0.99
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.97	D
PhyloP100		5.3
GERP RS		3.7
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.97		Position offset: -2

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

Other links and lift over

dbSNP: rs1601280018; hg19: chr22-19747202;