rs375860324

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM5

The NM_001199107.2(TBC1D24):​c.808C>T​(p.Arg270Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000744 in 1,613,896 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R270H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000079 ( 0 hom. )

Consequence

TBC1D24
NM_001199107.2 missense

Scores

2
9
8

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 5.82

Publications

1 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: Uncertain_significance. The variant received 2 ACMG points.

PM5
Other missense variant is known to change same aminoacid residue: Variant chr16-2496957-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 436947.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TBC1D24NM_001199107.2 linkc.808C>T p.Arg270Cys 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.808C>T p.Arg270Cys missense_variant Exon 2 of 8 NM_001199107.2 ENSP00000494678.1 Q9ULP9-1
ENSG00000260272ENST00000564543.1 linkc.808C>T p.Arg270Cys missense_variant Exon 1 of 3 2 ENSP00000455547.1 H3BQ06

Frequencies

GnomAD3 genomes
AF:
0.0000328
AC:
5
AN:
152252
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000482
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:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000401
AC:
10
AN:
249448
AF XY:
0.0000369
show subpopulations
Gnomad AFR exome
AF:
0.0000645
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:
0.0000618
Gnomad OTH exome
AF:
0.000165
GnomAD4 exome
AF:
0.0000787
AC:
115
AN:
1461644
Hom.:
0
Cov.:
31
AF XY:
0.0000674
AC XY:
49
AN XY:
727150
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.0000671
AC:
3
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000756
AC:
3
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53176
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000953
AC:
106
AN:
1112012
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.467
Heterozygous variant carriers
0
8
16
25
33
41
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.0000328
AC:
5
AN:
152252
Hom.:
0
Cov.:
33
AF XY:
0.0000403
AC XY:
3
AN XY:
74388
show subpopulations
African (AFR)
AF:
0.0000482
AC:
2
AN:
41466
American (AMR)
AF:
0.00
AC:
0
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5204
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10628
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000441
AC:
3
AN:
68042
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.535
Heterozygous variant carriers
0
1
2
3
4
5
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:
0.000116
Hom.:
0
Bravo
AF:
0.0000378
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000117
AC:
1
ExAC
AF:
0.0000247
AC:
3
EpiCase
AF:
0.0000545
EpiControl
AF:
0.000119

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

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 Uncertain:1
Jul 06, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Aug 09, 2025
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 24291220, 27281533) -

Developmental and epileptic encephalopathy, 1;C3892048:Autosomal dominant nonsyndromic hearing loss 65;CN236805:Caused by mutation in the TBC1 domain family, member 24 Uncertain:1
Aug 29, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 270 of the TBC1D24 protein (p.Arg270Cys). This variant is present in population databases (rs375860324, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with TBC1D24-related conditions. ClinVar contains an entry for this variant (Variation ID: 474312). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt TBC1D24 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.099
BayesDel_addAF
Benign
-0.089
T
BayesDel_noAF
Benign
-0.18
CADD
Pathogenic
26
DANN
Pathogenic
1.0
DEOGEN2
Benign
0.070
.;T;T;.;.;.;.
Eigen
Uncertain
0.50
Eigen_PC
Uncertain
0.46
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.86
.;.;D;D;D;D;D
M_CAP
Benign
0.055
D
MetaRNN
Uncertain
0.44
T;T;T;T;T;T;T
MetaSVM
Benign
-1.0
T
MutationAssessor
Uncertain
2.3
M;M;M;.;.;M;.
PhyloP100
5.8
PrimateAI
Uncertain
0.51
T
PROVEAN
Uncertain
-3.0
D;.;D;.;.;.;D
REVEL
Benign
0.16
Sift
Uncertain
0.026
D;.;T;.;.;.;T
Sift4G
Uncertain
0.0050
D;.;D;.;.;D;D
Polyphen
1.0
D;D;D;.;.;D;.
Vest4
0.75
MVP
0.58
MPC
1.1, 1.6
ClinPred
0.82
D
GERP RS
5.2
Varity_R
0.18
gMVP
0.37
Mutation Taster
=56/44
polymorphism

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: rs375860324; hg19: chr16-2546957; COSMIC: COSV53546283; COSMIC: COSV53546283; API