X-71366329-C-A

Variant names:

• chrX-71366329-C-A
• ENST00000373790.9:c.-46C>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The ENST00000715246.1(TAF1):​c.15C>A​(p.Cys5*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 20)
• Consequence: TAF1 ENST00000715246.1 stop_gained
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.110
• Publications: 0 publications found

Genes affected

TAF1 (HGNC:11535): (TATA-box binding protein associated factor 1) Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is the basal transcription factor TFIID, which binds to the core promoter to position the polymerase properly, serves as the scaffold for assembly of the remainder of the transcription complex, and acts as a channel for regulatory signals. TFIID is composed of the TATA-binding protein (TBP) and a group of evolutionarily conserved proteins known as TBP-associated factors or TAFs. TAFs may participate in basal transcription, serve as coactivators, function in promoter recognition or modify general transcription factors (GTFs) to facilitate complex assembly and transcription initiation. This gene encodes the largest subunit of TFIID. This subunit binds to core promoter sequences encompassing the transcription start site. It also binds to activators and other transcriptional regulators, and these interactions affect the rate of transcription initiation. This subunit contains two independent protein kinase domains at the N- and C-terminals, but also possesses acetyltransferase activity and can act as a ubiquitin-activating/conjugating enzyme. Mutations in this gene result in Dystonia 3, torsion, X-linked, a dystonia-parkinsonism disorder. Alternative splicing of this gene results in multiple transcript variants. This gene is part of a complex transcription unit (TAF1/DYT3), wherein some transcript variants share exons with TAF1 as well as additional downstream DYT3 exons. [provided by RefSeq, Oct 2013]

TAF1 Gene-Disease associations (from GenCC):

• intellectual disability, X-linked, syndromic 33

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, Illumina
• X-linked dystonia-parkinsonism

  Inheritance: XL, Unknown Classification: STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)
• X-linked intellectual disability-global development delay-facial dysmorphism-sacral caudal remnant syndrome

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 42 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TAF1	NM_004606.5	c.-46C>A		upstream_gene_variant		ENST00000423759.6	NP_004597.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TAF1	ENST00000423759.6	c.-46C>A		upstream_gene_variant		5	NM_004606.5	ENSP00000406549.2

Frequencies

GnomAD3 genomes Cov.: 20

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 20

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jul 21, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This variant has not been reported in the literature in individuals affected with TAF1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Cys5*) in the TAF1 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in TAF1 cause disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Benign	3.8
DANN	Uncertain	0.98
FATHMM_MKL	Benign	0.26	N
PhyloP100		0.11
Vest4		0.63
GERP RS		2.0
PromoterAI		-0.13	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=15/185	disease causing (fs/PTC)

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

hg19: chrX-70586179;