chr22-19765803-C-T

Variant names:

• chr22-19765803-C-T
• rs751339103
• NM_001379200.1:c.913C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001379200.1(TBX1):​c.913C>T​(p.Arg305Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,254 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R305Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TBX1 NM_001379200.1 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.35
• Publications: 10 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001379200.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBX1	NM_001379200.1	MANE Select	c.913C>T	p.Arg305Trp	missense	Exon 5 of 7	NP_001366129.1
	TBX1	NM_080647.1		c.886C>T	p.Arg296Trp	missense	Exon 7 of 9	NP_542378.1
	TBX1	NM_080646.2		c.886C>T	p.Arg296Trp	missense	Exon 7 of 9	NP_542377.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBX1	ENST00000649276.2	MANE Select	c.913C>T	p.Arg305Trp	missense	Exon 5 of 7	ENSP00000497003.1
	TBX1	ENST00000332710.8	TSL:1	c.886C>T	p.Arg296Trp	missense	Exon 7 of 9	ENSP00000331791.4
	TBX1	ENST00000329705.11	TSL:1	c.886C>T	p.Arg296Trp	missense	Exon 7 of 9	ENSP00000331176.7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000821 AC: 2 AN: 243664 AF XY: 0.00000756

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000558

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000916

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458254 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 725282

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33410

American (AMR) AF: 0.00 AC: 0 AN: 44486

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26076

East Asian (EAS) AF: 0.0000253 AC: 1 AN: 39510

South Asian (SAS) AF: 0.00 AC: 0 AN: 85664

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52374

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1110734

Other (OTH) AF: 0.00 AC: 0 AN: 60240

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00666416), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.93	D
Eigen	Uncertain	0.67
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.0	H
PhyloP100		2.3
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-7.1	D
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.91		Loss of disorder (P = 0.0204)
MVP		0.99
MPC		1.5
ClinPred		1.0	D
GERP RS		3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.88
Mutation Taster		=1/99	disease causing

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

Other links and lift over

dbSNP: rs751339103; hg19: chr22-19753326;