chr6-170561962-C-CG

Variant names:

• chr6-170561962-C-CG
• rs1779151861
• NM_003194.5:c.226_227insG

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003194.5(TBP):​c.226_227insG​(p.Gln76ArgfsTer102) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. Q76Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 21)
• Consequence: TBP NM_003194.5 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.36
• Publications: 0 publications found

Genes affected

TBP (HGNC:11588): (TATA-box binding protein) Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is transcription factor IID (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 TBP, the TATA-binding protein. A distinctive feature of TBP is a long string of glutamines in the N-terminus. This region of the protein modulates the DNA binding activity of the C terminus, and modulation of DNA binding affects the rate of transcription complex formation and initiation of transcription. The number of CAG repeats encoding the polyglutamine tract is usually 25-42, and expansion of the number of repeats to 45-66 increases the length of the polyglutamine string and is associated with spinocerebellar ataxia 17, a neurodegenerative disorder classified as a polyglutamine disease. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2016]

TBP Gene-Disease associations (from GenCC):

• spinocerebellar ataxia type 17

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003194.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBP	NM_003194.5	MANE Select	c.226_227insG	p.Gln76ArgfsTer102	frameshift	Exon 3 of 8	NP_003185.1	P20226-1
	TBP	NM_001172085.2		c.166_167insG	p.Gln56ArgfsTer102	frameshift	Exon 2 of 7	NP_001165556.1	P20226-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBP	ENST00000392092.7	TSL:1 MANE Select	c.226_227insG	p.Gln76ArgfsTer102	frameshift	Exon 3 of 8	ENSP00000375942.2	P20226-1
	TBP	ENST00000230354.10	TSL:1	c.226_227insG	p.Gln76ArgfsTer102	frameshift	Exon 3 of 8	ENSP00000230354.5	P20226-1
	TBP	ENST00000421512.5	TSL:1	c.226_227insG	p.Gln76ArgfsTer102	frameshift	Exon 3 of 5	ENSP00000400008.1	Q7Z6S5

Frequencies

GnomAD3 genomes Cov.: 21

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 21

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.4

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: rs1779151861; hg19: chr6-170871050;