rs575822089

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001163435.3(TBCK):c.376C>T(p.Arg126Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000781 in 1,510,172 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.00024 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000060 ( 0 hom. )

Consequence

TBCK
NM_001163435.3 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:13O:1

Conservation

PhyloP100: 2.90

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 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 4-106262103-G-A is Pathogenic according to our data. Variant chr4-106262103-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 225235.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr4-106262103-G-A is described in Lovd as [Pathogenic]. Variant chr4-106262103-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TBCK	NM_001163435.3 linkuse as main transcript	c.376C>T	p.Arg126Ter	stop_gained	4/26	ENST00000394708.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TBCK	ENST00000394708.7 linkuse as main transcript	c.376C>T	p.Arg126Ter	stop_gained	4/26	1	NM_001163435.3	P1	Q8TEA7-1

Frequencies

GnomAD3 genomes

AF:

0.000238

AC:

AN:

151396

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000486

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00198

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:

0.0000442

Gnomad OTH

AF:

0.000480

GnomAD3 exomes

AF:

0.0000772

AC:

AN:

142542

Hom.:

AF XY:

0.0000663

AC XY:

AN XY:

75414

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000279

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000178

Gnomad OTH exome

AF:

0.000995

GnomAD4 exome

AF:

0.0000604

AC:

AN:

1358660

Hom.:

Cov.:

AF XY:

0.0000567

AC XY:

AN XY:

670738

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000702

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000465

Gnomad4 OTH exome

AF:

0.000178

GnomAD4 genome

AF:

0.000238

AC:

AN:

151512

Hom.:

Cov.:

AF XY:

0.000243

AC XY:

AN XY:

74004

show subpopulations

Gnomad4 AFR

AF:

0.0000485

Gnomad4 AMR

AF:

0.00197

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000442

Gnomad4 OTH

AF:

0.000475

Alfa

AF:

0.0000889

Hom.:

Bravo

AF:

0.000782

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.000124

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:13Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hypotonia, infantile, with psychomotor retardation and characteristic facies 3

Pathogenic:7Other:1

Pathogenic, criteria provided, single submitter	clinical testing	New York Genome Center	Aug 26, 2021	The c.376C>T (p.Arg126Ter) variant identified in the TBCK gene results in the premature termination of the protein at amino acid 126/894 (coding exon 4/26). This is predicted to lead to the termination of the protein within the protein kinase domain and result in the absence of Rab-GAP TBC and RHOD domains. This variant is found with low frequency in gnomAD (13 heterozygotes, 0 homozygotes; allele frequency: 7.48e-5) suggesting it is not a common benign variant in the populations represented in this database. This variant is reported as Pathogenic/Likely Pathogenic in ClinVar (VarID:225235), and has been reported in more than 10 affected individuals in the literature [PMID:27040692; PMID:27040691; PMID:29283439; PMID:31618753] in both homozygosity [PMID:27040692; PMID:27040691; PMID:29283439] and in compound heterozygosity with a second pathogenic variant [PMID:27040691; PMID:29283439]. Functional studies suggest this variant leads to increased levels of autophagic flux. This variant was identifed in homozygosity in an individual submitted for clinical WGS. Given the deleterious nature of the homozygous c.376C>T (p.Arg126Ter) variant identified in this individual, its low frequency in population databases, and the observation in many affected individuals in the literature, it is reported here as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center	Jul 29, 2022	PVS1, PM2, PM3 -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Oct 31, 2018	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	May 19, 2016	- -
Pathogenic, no assertion criteria provided	clinical testing	Biochemical Molecular Genetic Laboratory, King Abdulaziz Medical City	Aug 07, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Oct 25, 2019	Variant summary: TBCK c.376C>T (p.Arg126X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 7.7e-05 in 142542 control chromosomes (gnomAD). This frequency is not higher than expected for a pathogenic variant in TBCK causing Hypotonia, infantile, with psychomotor retardation and characteristic facies 3 (7.7e-05 vs 0.0011). c.376C>T has been reported in the literature in multiple individuals, predominantly of Puerto Rican descent (in compound heterozygous or homozygous state) affected with Hypotonia, infantile, with psychomotor retardation and characteristic facies 3 (Chong_2016, Bhoj_2016, Ortiz-Gonzlez_2018). These data indicate that the variant is very likely to be associated with disease. Chong_2016 reports the variant perturbs the levels of both major TBCK protein isoforms in fibroblasts. Five ClinVar submitters (evaluation after 2014) cite the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
not provided, no classification provided	phenotyping only	GenomeConnect, ClinGen	-	Variant interpretted as Pathogenic and reported on 08-19-2019 by Lab or GTR ID 26957. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Dec 17, 2019	This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -

not provided

Pathogenic:4

Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 29, 2024	This sequence change creates a premature translational stop signal (p.Arg126*) in the TBCK gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TBCK are known to be pathogenic (PMID: 27040692, 30103036). This variant is present in population databases (rs575822089, gnomAD 0.03%). This premature translational stop signal has been observed in individuals with TBCK-related severe infantile syndromic encephalopathy or TBCK-related intellectual disability and hypotonia syndrome (PMID: 27040691, 27040692). ClinVar contains an entry for this variant (Variation ID: 225235). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 15, 2021	Nonsense 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; This variant is associated with the following publications: (PMID: 27040692, 27040691, 29283439, 30577886) -
Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -

Syndromic Infantile Encephalopathy

Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

University of Washington Center for Mendelian Genomics, University of Washington

Apr 07, 2016

- -

Inborn genetic diseases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 01, 2021

The c.376C>T (p.R126*) alteration, located in exon 4 (coding exon 3) of the TBCK gene, consists of a C to T substitution at nucleotide position 376. This changes the amino acid from a Arginine (R) to a stop codon at amino acid position 126. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, the T allele has an overall frequency of 0.007% (13/173798) total alleles studied. This alteration has been described in the homozygous state and compound heterozygous with a second TBCK variant in multiple unrelated individuals, primarily of Puerto Rican descent (Bhoj, 2016; Chong, 2016; Ortiz-Gonzalez, 2018; Baker, 2019; Ziats, 2020). Additionally, we have identified this variant in the homozygous state via whole exome sequencing at Ambry Genetics in four patients with clinical features of TBCK-related neurodevelopmental disorders. Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.43

Cadd

Pathogenic

Dann

Uncertain

1.0

Eigen

Uncertain

0.68

Eigen_PC

Uncertain

0.52

FATHMM_MKL

Benign

0.54

MutationTaster

Benign

1.0

A;A;A;A;D

Vest4

0.17

GERP RS

4.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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