16-2496206-C-T

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_001199107.2(TBC1D24):​c.58C>T​(p.Gln20*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000223 in 1,613,834 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 (★★).

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

TBC1D24
NM_001199107.2 stop_gained

Scores

4
2
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 3.59

Publications

7 publications found
Variant links:
Genes affected
TBC1D24 (HGNC:29203): (TBC1 domain family member 24) This gene encodes a protein with a conserved domain, referred to as the TBC domain, characteristic of proteins which interact with GTPases. TBC domain proteins may serve as GTPase-activating proteins for a particular group of GTPases, the Rab (Ras-related proteins in brain) small GTPases which are involved in the regulation of membrane trafficking. Mutations in this gene are associated with familial infantile myoclonic epilepsy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2011]
TBC1D24 Gene-Disease associations (from GenCC):
  • DOORS syndrome
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet, PanelApp Australia, G2P
  • familial infantile myoclonic epilepsy
    Inheritance: AR Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet
  • autosomal dominant nonsyndromic hearing loss 65
    Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • autosomal dominant nonsyndromic hearing loss
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • malignant migrating partial seizures of infancy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • focal epilepsy-intellectual disability-cerebro-cerebellar malformation
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hearing loss, autosomal recessive
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • progressive myoclonic epilepsy with dystonia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • nonsyndromic genetic hearing loss
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen
  • autosomal recessive nonsyndromic hearing loss 86
    Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 110 pathogenic variants in the truncated region.
PP5
Variant 16-2496206-C-T is Pathogenic according to our data. Variant chr16-2496206-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 419782.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
TBC1D24NM_001199107.2 linkc.58C>T p.Gln20* stop_gained Exon 2 of 8 ENST00000646147.1 NP_001186036.1 Q9ULP9-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TBC1D24ENST00000646147.1 linkc.58C>T p.Gln20* stop_gained Exon 2 of 8 NM_001199107.2 ENSP00000494678.1 Q9ULP9-1
ENSG00000260272ENST00000564543.1 linkc.58C>T p.Gln20* stop_gained Exon 1 of 3 2 ENSP00000455547.1 H3BQ06

Frequencies

GnomAD3 genomes
AF:
0.0000460
AC:
7
AN:
152232
Hom.:
0
Cov.:
33
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:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.000282
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000588
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000601
AC:
15
AN:
249420
AF XY:
0.0000960
show subpopulations
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:
0.000325
Gnomad NFE exome
AF:
0.0000442
Gnomad OTH exome
AF:
0.000496
GnomAD4 exome
AF:
0.0000198
AC:
29
AN:
1461602
Hom.:
0
Cov.:
31
AF XY:
0.0000206
AC XY:
15
AN XY:
727120
show subpopulations
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:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86250
European-Finnish (FIN)
AF:
0.000282
AC:
15
AN:
53160
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000899
AC:
10
AN:
1111994
Other (OTH)
AF:
0.0000662
AC:
4
AN:
60390
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.503
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:
0.0000460
AC:
7
AN:
152232
Hom.:
0
Cov.:
33
AF XY:
0.0000538
AC XY:
4
AN XY:
74370
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41456
American (AMR)
AF:
0.00
AC:
0
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5192
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.000282
AC:
3
AN:
10628
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000588
AC:
4
AN:
68038
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000733
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000826
AC:
10
EpiCase
AF:
0.000109
EpiControl
AF:
0.00

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:1
Jan 30, 2017
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Q20X pathogenic variant in the TBC1D24 gene has been reported previously (also reported incorrectly as Q20E), in the compound heterozygous state along with a missense variant, in two brothers with DOORS syndrome. Clinical features included developmental delay/intellectual disability, abnormal nails, abnormal fingers and toes, deafness, and seizures (Campeau et al., 2014; Balestrini et al., 2016). This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The Q20X variant was not observed in approximately 6400 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret Q20X as a pathogenic variant. -

Developmental and epileptic encephalopathy, 1;C3892048:Autosomal dominant nonsyndromic hearing loss 65;CN236805:Caused by mutation in the TBC1 domain family, member 24 Pathogenic:1
Jul 13, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This premature translational stop signal has been observed in individual(s) with clinical features of TBC1D24-related conditions (PMID: 27281533). This sequence change creates a premature translational stop signal (p.Gln20*) in the TBC1D24 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TBC1D24 are known to be pathogenic (PMID: 23526554, 24291220). This variant is present in population databases (rs201257588, gnomAD 0.03%). ClinVar contains an entry for this variant (Variation ID: 419782). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.53
D
BayesDel_noAF
Pathogenic
0.39
CADD
Pathogenic
37
DANN
Uncertain
1.0
Eigen
Pathogenic
0.93
Eigen_PC
Pathogenic
0.81
FATHMM_MKL
Uncertain
0.94
D
PhyloP100
3.6
Vest4
0.59
GERP RS
5.6
PromoterAI
0.027
Neutral
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: rs201257588; hg19: chr16-2546207; COSMIC: COSV53547713; COSMIC: COSV53547713; API