15-42775311-G-C

Variant names:

• chr15-42775311-G-C
• rs184167929
• NM_173500.4:c.1822C>G

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_173500.4(TTBK2):​c.1822C>G​(p.His608Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000638 in 1,614,048 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H608N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000064 (0 hom.)
• Consequence: TTBK2 NM_173500.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.83
• Publications: 2 publications found

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 Gene-Disease associations (from GenCC):

• spinocerebellar ataxia type 11

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.12864375).
• BS2: High AC in GnomAd4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTBK2	NM_173500.4	c.1822C>G	p.His608Asp	missense_variant	Exon 13 of 15	ENST00000267890.11	NP_775771.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTBK2	ENST00000267890.11	c.1822C>G	p.His608Asp	missense_variant	Exon 13 of 15	5	NM_173500.4	ENSP00000267890.6

Frequencies

GnomAD3 genomes AF: 0.0000591 AC: 9 AN: 152168 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.000103

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000120 AC: 3 AN: 249556 AF XY: 0.00000739

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000265

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000643 AC: 94 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.0000523 AC XY: 38 AN XY: 727240

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000800 AC: 89 AN: 1112010

Other (OTH) AF: 0.0000662 AC: 4 AN: 60396

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152168 Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4 AN XY: 74338

African (AFR) AF: 0.0000483 AC: 2 AN: 41438

American (AMR) AF: 0.00 AC: 0 AN: 15272

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5204

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000103 AC: 7 AN: 68020

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.0000450 Hom.: 0

Bravo AF: 0.0000869

ExAC AF: 0.00000828 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Aug 30, 2016

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases Uncertain:1

Sep 16, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1822C>G (p.H608D) alteration is located in exon 13 (coding exon 12) of the TTBK2 gene. This alteration results from a C to G substitution at nucleotide position 1822, causing the histidine (H) at amino acid position 608 to be replaced by an aspartic acid (D). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Benign	-0.41
CADD	Benign	19
DANN	Uncertain	0.98
DEOGEN2	Benign	0.16	T;T
Eigen	Benign	-0.34
Eigen_PC	Benign	-0.23
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Benign	0.64	T;T
M_CAP	Benign	0.0073	T
MetaRNN	Benign	0.13	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Uncertain	2.1	M;.
PhyloP100		2.8
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-1.4	N;.
REVEL	Benign	0.051
Sift	Uncertain	0.0080	D;.
Sift4G	Benign	0.22	T;T
Polyphen		0.026	B;.
Vest4		0.37
MVP		0.13
MPC		0.34
ClinPred		0.10	T
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.15
gMVP		0.53
Mutation Taster		=93/7	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: rs184167929; hg19: chr15-43067509;