chr6-170561964-G-C

Variant names:

• chr6-170561964-G-C
• rs112083427
• NM_003194.5:c.228G>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_003194.5(TBP):​c.228G>C​(p.Gln76His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. 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.

• Frequency:
  • Genomes: not found (cov: 21)
  • Exomes 𝑓: 0.0000013 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TBP NM_003194.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.02
• Publications: 10 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: Laboratory for Molecular Medicine, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.22635454).

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBP	NM_003194.5	MANE Select	c.228G>C	p.Gln76His	missense	Exon 3 of 8	NP_003185.1
	TBP	NM_001172085.2		c.168G>C	p.Gln56His	missense	Exon 2 of 7	NP_001165556.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBP	ENST00000392092.7	TSL:1 MANE Select	c.228G>C	p.Gln76His	missense	Exon 3 of 8	ENSP00000375942.2
	TBP	ENST00000230354.10	TSL:1	c.228G>C	p.Gln76His	missense	Exon 3 of 8	ENSP00000230354.5
	TBP	ENST00000421512.5	TSL:1	c.228G>C	p.Gln76His	missense	Exon 3 of 5	ENSP00000400008.1

Frequencies

GnomAD3 genomes Cov.: 21

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000132 AC: 1 AN: 756448 Hom.: 0 Cov.: 20 AF XY: 0.00 AC XY: 0 AN XY: 374038

⚠️ 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: 8366

American (AMR) AF: 0.00 AC: 0 AN: 16484

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 10240

East Asian (EAS) AF: 0.00 AC: 0 AN: 15136

South Asian (SAS) AF: 0.00 AC: 0 AN: 41590

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 27178

Middle Eastern (MID) AF: 0.000383 AC: 1 AN: 2612

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 603832

Other (OTH) AF: 0.00 AC: 0 AN: 31010

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

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
AlphaMissense	Benign	0.29
BayesDel_addAF	Benign	-0.0022	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	9.8
DANN	Benign	0.59
DEOGEN2	Benign	0.33	T
Eigen	Benign	-0.49
Eigen_PC	Benign	-0.53
FATHMM_MKL	Benign	0.48	N
LIST_S2	Benign	0.81	T
M_CAP	Uncertain	0.090	D
MetaRNN	Benign	0.23	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.34	N
PhyloP100		1.0
PrimateAI	Benign	0.48	T
PROVEAN	Benign	0.67	N
REVEL	Benign	0.085
Sift	Benign	0.14	T
Sift4G	Benign	0.18	T
Polyphen		0.68	P
Vest4		0.24
MutPred		0.37		Loss of solvent accessibility (P = 0.4653)
MVP		0.69
MPC		0.12
ClinPred		0.41	T
GERP RS		0.42
Varity_R		0.066
gMVP		0.44
Mutation Taster		=94/6	polymorphism

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: rs112083427; hg19: chr6-170871052;