6-84736951-T-C

Position:

chr6-84736951-T-C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_StrongBS1_SupportingBS2

The NM_001080508.3(TBX18):c.1558A>G(p.Thr520Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000137 in 1,608,930 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

TBX18
NM_001080508.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 1.58

Variant links:

Genes affected

TBX18 (HGNC:11595): (T-box transcription factor 18) This genes codes for a member of an evolutionarily conserved family of transcription factors that plays a crucial role in embryonic development. The family is characterized by the presence of the DNA-binding T-box domain and is divided into five sub-families based on sequence conservation in this domain. The encoded protein belongs to the vertebrate specific Tbx1 sub-family. The protein acts as a transcriptional repressor by antagonizing transcriptional activators in the T-box family. The protein forms homo- or heterodimers with other transcription factors of the T-box family or other transcription factors. [provided by RefSeq, Nov 2012]

TBX18 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.036273777).

BS1

Variant frequency is greater than expected in population amr. gnomad4_exome allele frequency = 0.0000144 (21/1456932) while in subpopulation AMR AF= 0.000473 (21/44430). AF 95% confidence interval is 0.000316. There are 0 homozygotes in gnomad4_exome. There are 10 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAdExome4 at 21 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TBX18	NM_001080508.3 linkuse as main transcript	c.1558A>G	p.Thr520Ala	missense_variant	8/8	ENST00000369663.10	NP_001073977.1	O95935

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TBX18	ENST00000369663.10 linkuse as main transcript	c.1558A>G	p.Thr520Ala	missense_variant	8/8	1	NM_001080508.3	ENSP00000358677.4		O95935
TBX18	ENST00000606784.5 linkuse as main transcript	c.625+1546A>G		intron_variant		1		ENSP00000475873.1		U3KQH2

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151998

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000647

AC:

AN:

247336

Hom.:

AF XY:

0.0000525

AC XY:

AN XY:

133410

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000467

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1456932

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

724058

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000473

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151998

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74234

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000302

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 12, 2022

The c.1558A>G (p.T520A) alteration is located in exon 8 (coding exon 8) of the TBX18 gene. This alteration results from a A to G substitution at nucleotide position 1558, causing the threonine (T) at amino acid position 520 to be replaced by an alanine (A). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 15, 2024

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 520 of the TBX18 protein (p.Thr520Ala). This variant is present in population databases (rs537759635, gnomAD 0.05%). This variant has not been reported in the literature in individuals affected with TBX18-related conditions. ClinVar contains an entry for this variant (Variation ID: 2064043). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TBX18 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.060

BayesDel_addAF

Benign

-0.34

BayesDel_noAF

Benign

-0.41

CADD

Benign

DANN

Benign

0.10

DEOGEN2

Benign

0.036

Eigen

Benign

-0.79

Eigen_PC

Benign

-0.60

FATHMM_MKL

Uncertain

0.77

LIST_S2

Benign

0.72

M_CAP

Benign

0.020

MetaRNN

Benign

0.036

MetaSVM

Benign

-0.99

MutationAssessor

Benign

-0.69

PrimateAI

Uncertain

0.53

PROVEAN

Benign

1.0

REVEL

Benign

0.15

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.0010

Vest4

0.097

MutPred

0.29

Loss of stability (P = 0.0507);

MVP

0.30

MPC

0.044

ClinPred

0.021

GERP RS

2.9

Varity_R

0.024

gMVP

0.26

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over