NM_001163435.3:c.1370dupA

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001163435.3(TBCK):​c.1370dupA​(p.Asn457LysfsTer10) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000187 in 1,606,174 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

TBCK
NM_001163435.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.75

Publications

9 publications found
Variant links:
Genes affected
TBCK (HGNC:28261): (TBC1 domain containing kinase) This gene encodes a protein that contains a protein kinase domain, a Rhodanase-like domain and the Tre-2/Bub2/Cdc16 (TBC) domain. The encoded protein is thought to play a role in actin organization, cell growth and cell proliferation by regulating the mammalian target of the rapamycin (mTOR) signaling pathway. This protein may also be involved in the transcriptional regulation of the components of the mTOR complex. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]
TBCK Gene-Disease associations (from GenCC):
  • hypotonia, infantile, with psychomotor retardation and characteristic facies 3
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 4-106235347-G-GT is Pathogenic according to our data. Variant chr4-106235347-G-GT is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 986992.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TBCKNM_001163435.3 linkc.1370dupA p.Asn457LysfsTer10 frameshift_variant Exon 15 of 26 ENST00000394708.7 NP_001156907.2 Q8TEA7-1A0A024RDH3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TBCKENST00000394708.7 linkc.1370dupA p.Asn457LysfsTer10 frameshift_variant Exon 15 of 26 1 NM_001163435.3 ENSP00000378198.2 Q8TEA7-1

Frequencies

GnomAD3 genomes
AF:
0.0000132
AC:
2
AN:
151430
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.000387
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000623
AC:
15
AN:
240840
AF XY:
0.0000460
show subpopulations
Gnomad AFR exome
AF:
0.000127
Gnomad AMR exome
AF:
0.0000602
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000396
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000276
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000192
AC:
28
AN:
1454744
Hom.:
0
Cov.:
30
AF XY:
0.0000193
AC XY:
14
AN XY:
723680
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000602
AC:
2
AN:
33212
American (AMR)
AF:
0.0000452
AC:
2
AN:
44236
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25896
East Asian (EAS)
AF:
0.0000508
AC:
2
AN:
39334
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85514
European-Finnish (FIN)
AF:
0.0000382
AC:
2
AN:
52416
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5732
European-Non Finnish (NFE)
AF:
0.0000162
AC:
18
AN:
1108388
Other (OTH)
AF:
0.0000333
AC:
2
AN:
60016
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000000341559), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.352
Heterozygous variant carriers
0
3
5
8
10
13
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000132
AC:
2
AN:
151430
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
73892
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41190
American (AMR)
AF:
0.00
AC:
0
AN:
15174
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.000387
AC:
2
AN:
5172
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4804
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10508
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
67804
Other (OTH)
AF:
0.00
AC:
0
AN:
2086
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.650
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000329
Hom.:
0

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:2
Oct 23, 2020
Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Apr 26, 2022
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Has not been previously published as pathogenic or benign to our knowledge -

Hypotonia, infantile, with psychomotor retardation and characteristic facies 3 Pathogenic:2
Feb 02, 2022
Victorian Clinical Genetics Services, Murdoch Childrens Research Institute
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with hypotonia, infantile, with psychomotor delay and characteristic facies 3 (MIM#616900). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0201 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction). (SP) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v2) <0.01 for a recessive condition (17 heterozygotes, 0 homozygotes). (SP) 0701 - Other NMD-predicted variants comparable to the one identified in this case have very strong previous evidence for pathogenicity. These variants have been reported many times as pathogenic, and observed in individuals with intellectual disability and hypotonia syndrome (DECIPHER, PMID: 27040691). (SP) 0803 - This variant has limited previous evidence of pathogenicity in an unrelated individual. This variant has been reported as likely pathogenic, and observed in a single individual with global developmental delay (ClinVar, LOVD). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Jan 13, 2025
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:curation

The p.Asn457LysfsTer10 variant in TBCK has not been previously reported in the literature in individuals with TBCK-related intellectual disability syndrome, and has been identified in 0.009% (4/44506) of East Asian chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs746860249). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. It is of note that this variant occurs in a homopolymer repeat, which could indicate that it is an artifact from sequencing. However, disease-causing variants have been reported in homopolymer regions, so this is not enough to rule out a pathogenic role. This variant has also been reported in ClinVar (Variation ID: 986992) and has been interpreted as pathogenic/likely pathogenic by Victorian Clinical Genetics Services (Murdoch Childrens Research Institute), GeneDx, and Institute of Medical Genetics and Applied Genomics (University Hospital Tübingen). This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 457 and leads to a premature termination codon 10 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the TBCK gene is an established disease mechanism in autosomal recessive TBCK-related intellectual disability syndrome. In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive TBCK-related intellectual disability syndrome. ACMG/AMP Criteria applied: PVS1, PM2_supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
PhyloP100
5.7
Mutation Taster
=2/198
disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs746860249; hg19: chr4-107156504; COSMIC: COSV56752969; COSMIC: COSV56752969; API