chr15-42752627-C-G

Variant names:

• chr15-42752627-C-G
• rs1167737727
• NM_173500.4:c.2619G>C

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_173500.4(TTBK2):​c.2619G>C​(p.Met873Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M873T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TTBK2 NM_173500.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.354
• Publications: 0 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: Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.03151405).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_173500.4. 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
	TTBK2	NM_173500.4	MANE Select	c.2619G>C	p.Met873Ile	missense	Exon 14 of 15	NP_775771.3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTBK2	ENST00000267890.11	TSL:5 MANE Select	c.2619G>C	p.Met873Ile	missense	Exon 14 of 15	ENSP00000267890.6	Q6IQ55-1
	TTBK2	ENST00000903061.1		c.2619G>C	p.Met873Ile	missense	Exon 14 of 15	ENSP00000573120.1
	TTBK2	ENST00000903062.1		c.2553G>C	p.Met851Ile	missense	Exon 13 of 14	ENSP00000573121.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461822 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727214

African (AFR) AF: 0.00 AC: 0 AN: 33480

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53358

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

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112010

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.31	T
BayesDel_noAF	Benign	-0.69
CADD	Benign	3.2
DANN	Benign	0.43
DEOGEN2	Benign	0.039	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.077	N
LIST_S2	Benign	0.50	T
M_CAP	Benign	0.0038	T
MetaRNN	Benign	0.032	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.95	L
PhyloP100		-0.35
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-0.20	N
REVEL	Benign	0.032
Sift	Benign	0.61	T
Sift4G	Benign	0.23	T
Polyphen		0.0	B
Vest4		0.050
MutPred		0.21		Loss of ubiquitination at K875 (P = 0.0531)
MVP		0.22
MPC		0.26
ClinPred		0.017	T
GERP RS		1.9
Varity_R		0.031
gMVP		0.035

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: rs1167737727; hg19: chr15-43044825;