rs200821440

Variant names:

Variant summary

Our verdict is Benign. Variant got -11 ACMG points: 0P and 11B. BP4_ModerateBP6BS1BS2

The NM_173500.4(TTBK2):c.245G>C(p.Gly82Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000266 in 1,613,836 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00029 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00026 ( 0 hom. )

Consequence

TTBK2
NM_173500.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:2

Conservation

PhyloP100: 7.21

Variant links:

Genes affected

TTBK2 (HGNC:19141): (tau tubulin kinase 2) This gene encodes a serine-threonine kinase that putatively phosphorylates tau and tubulin proteins. Mutations in this gene cause spinocerebellar ataxia type 11 (SCA11); a neurodegenerative disease characterized by progressive ataxia and atrophy of the cerebellum and brainstem. [provided by RefSeq, Aug 2009]

TTBK2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -11 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.17650867).

BP6

Variant 15-42840406-C-G is Benign according to our data. Variant chr15-42840406-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 448754.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=2}. Variant chr15-42840406-C-G is described in Lovd as [Likely_benign].

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000289 (44/152138) while in subpopulation NFE AF= 0.000427 (29/67990). AF 95% confidence interval is 0.000304. There are 0 homozygotes in gnomad4. There are 29 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

BS2

High AC in GnomAd4 at 44 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTBK2	NM_173500.4 link	c.245G>C	p.Gly82Ala	missense_variant	Exon 4 of 15	ENST00000267890.11	NP_775771.3	Q6IQ55-1Q8IWY7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTBK2	ENST00000267890.11 link	c.245G>C	p.Gly82Ala	missense_variant	Exon 4 of 15	5	NM_173500.4	ENSP00000267890.6		Q6IQ55-1

Frequencies

GnomAD3 genomes

AF:

0.000303

AC:

AN:

152020

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000169

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000208

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.0158

Gnomad NFE

AF:

0.000426

Gnomad OTH

AF:

0.000956

GnomAD3 exomes

AF:

0.000257

AC:

AN:

249482

Hom.:

AF XY:

0.000310

AC XY:

AN XY:

135344

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.0000869

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000261

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000415

Gnomad OTH exome

AF:

0.000826

GnomAD4 exome

AF:

0.000263

AC:

385

AN:

1461698

Hom.:

Cov.:

AF XY:

0.000271

AC XY:

197

AN XY:

727154

show subpopulations

Gnomad4 AFR exome

AF:

0.000597

Gnomad4 AMR exome

AF:

0.000134

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000301

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000255

Gnomad4 OTH exome

AF:

0.000397

GnomAD4 genome

AF:

0.000289

AC:

AN:

152138

Hom.:

Cov.:

AF XY:

0.000390

AC XY:

AN XY:

74384

show subpopulations

Gnomad4 AFR

AF:

0.000169

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000208

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000427

Gnomad4 OTH

AF:

0.000946

Alfa

AF:

0.000472

Hom.:

Bravo

AF:

0.000208

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000367

AC:

ExAC

AF:

0.000290

AC:

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000709

EpiControl

AF:

0.000830

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Dec 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 82 of the TTBK2 protein (p.Gly82Ala). This variant is present in population databases (rs200821440, gnomAD 0.04%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with spinocerebellar ataxia (PMID: 28362824). ClinVar contains an entry for this variant (Variation ID: 448754). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt TTBK2 protein function with a positive 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. -

Aug 29, 2022

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported as a variant of uncertain significance in an individual with ataxia in published literature (Iqbal et al., 2017); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 28362824) -

Breakthrough Genomics, Breakthrough Genomics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

not specified

Benign:1

Feb 01, 2017

Athena Diagnostics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.86

BayesDel_addAF

Benign

-0.19

BayesDel_noAF

Uncertain

0.020

CADD

Pathogenic

DANN

Benign

0.95

Eigen

Uncertain

0.47

Eigen_PC

Uncertain

0.56

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.27

M_CAP

Uncertain

0.15

MetaRNN

Benign

0.18

PROVEAN

Benign

-0.030

MVP

0.57

ClinPred

0.26

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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