16-2496264-C-T

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM5PP5_Very_Strong

The NM_001199107.2(TBC1D24):​c.116C>T​(p.Ala39Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,613,788 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A39E) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

TBC1D24
NM_001199107.2 missense

Scores

4
9
6

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 7.56

Publications

4 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 10 ACMG points.

PM5
Other missense variant is known to change same aminoacid residue: Variant chr16-2496263-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 1066340.Status of the report is criteria_provided_single_submitter, 1 stars.
PP5
Variant 16-2496264-C-T is Pathogenic according to our data. Variant chr16-2496264-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 474302.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.116C>T p.Ala39Val missense_variant 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.116C>T p.Ala39Val missense_variant Exon 2 of 8 NM_001199107.2 ENSP00000494678.1 Q9ULP9-1
ENSG00000260272ENST00000564543.1 linkc.116C>T p.Ala39Val missense_variant Exon 1 of 3 2 ENSP00000455547.1 H3BQ06

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152248
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000241
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000120
AC:
3
AN:
249060
AF XY:
0.00000739
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000290
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000177
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000116
AC:
17
AN:
1461422
Hom.:
0
Cov.:
31
AF XY:
0.00000688
AC XY:
5
AN XY:
727032
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.0000224
AC:
1
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:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52976
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000126
AC:
14
AN:
1111992
Other (OTH)
AF:
0.0000331
AC:
2
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.510
Heterozygous variant carriers
0
2
4
6
8
10
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:
0.0000131
AC:
2
AN:
152366
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74506
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41586
American (AMR)
AF:
0.00
AC:
0
AN:
15308
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68034
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.492
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:
0.00
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000248
AC:
3

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 86 Pathogenic:1
Sep 22, 2024
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 autosomal recessive deafness 86 (MIM#614617), DOORS syndrome (MIM#220500), epilepsy, rolandic, with proxysmal exercise-induce dystonia and writer's cramp (MIM#608105), developmental and epileptic encephalopathy 16 (MIM#615338) and familial, infantile myoclonic epilepsy (MIM#605021). Dominant negative or gain of function is suggested mechanism of autosomal dominant deafness, 65 (MIM#616044) (PMID: 27281533). (I) 0106 - This gene is associated with autosomal recessive disease. Autosomal dominant disease is a rare association. (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to valine. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v2) <0.01 for a recessive condition (3 heterozygotes, 0 homozygotes). (SP) 0309 - Multiple alternative amino acid changes at the same position have been observed in gnomAD (v2) (highest allele count: 6 heterozygotes, 0 homozygotes). (I) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. (I) 0602 - Variant is located in a hotspot region or cluster of pathogenic variants (DECIPHER). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as pathogenic by clinical laboratories in ClinVar and has been observed in many individuals with TBC1D24-related conditions (PMIDs: 28292732, 31112829). (SP) 1201 - Heterozygous variant detected in trans with a second likely pathogenic heterozygous variant (c.877C>T; p.(Arg293Cys)) in a recessive disease. (I) 1205 - This variant has been shown to be maternally inherited (by segregation analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

DOORS syndrome;C0917800:Familial infantile myoclonic epilepsy;C1842531:Rolandic epilepsy-paroxysmal exercise-induced dystonia-writer's cramp syndrome;C2829265:Autosomal recessive nonsyndromic hearing loss 86;C3809173:Developmental and epileptic encephalopathy, 16;C3892048:Autosomal dominant nonsyndromic hearing loss 65 Pathogenic:1
-
Juno Genomics, Hangzhou Juno Genomics, Inc
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

PM2_Supporting+PM3_VeryStrong+PP4 -

not provided Pathogenic:1
Aug 07, 2020
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 31618474, 31112829, 28292732, 30180405, 29429257, 30776697) -

Epilepsy Pathogenic:1
May 01, 2025
Department of Reproductive Genetics, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

The NM_001199107.2(TBC1D24):c.116C>T(p.Ala39Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,613,788 control chromosomes in the GnomAD database, with no homozygous occurrence. This variant has been reported in the literature as biallelic or a compound heterozygous state in multiple patients (PMID:31112829; 33063868;28292732). -

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
Aug 30, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 39 of the TBC1D24 protein (p.Ala39Val). This variant is present in population databases (rs773916549, gnomAD 0.003%). This missense change has been observed in individual(s) with clinical features of autosomal recessive TBC1D24-related conditions (PMID: 28292732, 30776697, 31112829). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 474302). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TBC1D24 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.76
BayesDel_addAF
Uncertain
0.056
T
BayesDel_noAF
Uncertain
-0.070
CADD
Pathogenic
29
DANN
Pathogenic
1.0
DEOGEN2
Benign
0.0011
.;T;T;.;.;.;.
Eigen
Uncertain
0.65
Eigen_PC
Uncertain
0.65
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.94
.;.;D;D;D;D;D
M_CAP
Pathogenic
0.40
D
MetaRNN
Uncertain
0.62
D;D;D;D;D;D;D
MetaSVM
Benign
-1.0
T
MutationAssessor
Uncertain
2.5
M;M;M;.;.;M;.
PhyloP100
7.6
PrimateAI
Uncertain
0.64
T
PROVEAN
Benign
0.15
N;.;N;D;.;.;N
REVEL
Benign
0.21
Sift
Benign
0.18
T;.;T;D;.;.;T
Sift4G
Uncertain
0.013
D;.;D;D;.;D;D
Polyphen
1.0
D;D;D;.;.;D;.
Vest4
0.81
MutPred
0.68
Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);Gain of methylation at K36 (P = 0.0828);
MVP
0.77
MPC
1.1, 1.4
ClinPred
0.76
D
GERP RS
5.6
PromoterAI
-0.0067
Neutral
Varity_R
0.19
gMVP
0.63
Mutation Taster
=1/99
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: rs773916549; hg19: chr16-2546265; COSMIC: COSV53548182; COSMIC: COSV53548182; API