chrX-106822128-G-A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_017752.3(TBC1D8B):​c.512G>A​(p.Arg171Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000149 in 1,208,054 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 10 hemizygotes in GnomAD. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000090 ( 0 hom., 0 hem., cov: 23)
Exomes 𝑓: 0.000015 ( 0 hom. 10 hem. )

Consequence

TBC1D8B
NM_017752.3 missense

Scores

3
9
5

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.63

Publications

1 publications found
Variant links:
Genes affected
TBC1D8B (HGNC:24715): (TBC1 domain family member 8B) This gene encodes a protein with a TBC (Tre-2/Bub2/CDC16) domain. Some mammalian proteins with this domain have been shown to function as Rab-GAPs by binding to specific Rab proteins and affecting their GTPase activity. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2011]
MORC4 (HGNC:23485): (MORC family CW-type zinc finger 4) In human, the four current members of the microrchidia (morc) gene family share an N-terminal ATPase-like ATP-binding region and a CW four-cysteine zinc-finger motif. The protein encoded by this gene also has a nuclear matrix binding domain and a two-stranded coiled-coil motif near its C-terminus. This gene is widely expressed at low levels in normal tissues and has elevated expression in placenta and testis. Alternative splicing results in multiple transcript variants encoding distinct proteins. [provided by RefSeq, Jan 2010]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BS2
High AC in GnomAdExome4 at 17 XL,AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TBC1D8BNM_017752.3 linkc.512G>A p.Arg171Gln missense_variant Exon 4 of 21 ENST00000357242.10 NP_060222.2 Q0IIM8-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TBC1D8BENST00000357242.10 linkc.512G>A p.Arg171Gln missense_variant Exon 4 of 21 1 NM_017752.3 ENSP00000349781.5 Q0IIM8-1

Frequencies

GnomAD3 genomes
AF:
0.00000900
AC:
1
AN:
111122
Hom.:
0
Cov.:
23
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:
0.000286
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:
0.0000110
AC:
2
AN:
182215
AF XY:
0.0000298
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000368
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000123
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000155
AC:
17
AN:
1096932
Hom.:
0
Cov.:
30
AF XY:
0.0000276
AC XY:
10
AN XY:
362740
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
26334
American (AMR)
AF:
0.0000285
AC:
1
AN:
35094
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
19324
East Asian (EAS)
AF:
0.0000994
AC:
3
AN:
30173
South Asian (SAS)
AF:
0.0000742
AC:
4
AN:
53944
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
40498
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
4129
European-Non Finnish (NFE)
AF:
0.00000951
AC:
8
AN:
841405
Other (OTH)
AF:
0.0000217
AC:
1
AN:
46031
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
1
2
2
3
4
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
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:
0.00000900
AC:
1
AN:
111122
Hom.:
0
Cov.:
23
AF XY:
0.00
AC XY:
0
AN XY:
33398
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
30640
American (AMR)
AF:
0.00
AC:
0
AN:
10391
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
2637
East Asian (EAS)
AF:
0.000286
AC:
1
AN:
3497
South Asian (SAS)
AF:
0.00
AC:
0
AN:
2644
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
5975
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
236
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
52920
Other (OTH)
AF:
0.00
AC:
0
AN:
1497
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.275
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:
0.00
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not provided Uncertain:1
Oct 06, 2022
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 glutamine, which is neutral and polar, at codon 171 of the TBC1D8B protein (p.Arg171Gln). This variant has not been reported in the literature in individuals affected with TBC1D8B-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.15
BayesDel_addAF
Benign
-0.0046
T
BayesDel_noAF
Benign
-0.13
CADD
Pathogenic
27
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.81
D;.;D;D
FATHMM_MKL
Uncertain
0.95
D
LIST_S2
Pathogenic
0.98
D;D;D;D
M_CAP
Uncertain
0.16
D
MetaRNN
Uncertain
0.49
T;T;T;T
MetaSVM
Uncertain
0.60
D
MutationAssessor
Benign
1.6
L;L;.;.
PhyloP100
6.6
PrimateAI
Uncertain
0.61
T
PROVEAN
Uncertain
-2.8
D;D;D;D
REVEL
Uncertain
0.64
Sift
Uncertain
0.0030
D;D;D;D
Sift4G
Uncertain
0.010
D;D;D;D
Polyphen
0.98
D;.;P;.
Vest4
0.59
MutPred
0.54
Gain of ubiquitination at K169 (P = 0.0708);Gain of ubiquitination at K169 (P = 0.0708);Gain of ubiquitination at K169 (P = 0.0708);Gain of ubiquitination at K169 (P = 0.0708);
MVP
0.51
MPC
0.45
ClinPred
0.78
D
GERP RS
5.3
Varity_R
0.57
gMVP
0.32
Mutation Taster
=91/9
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: rs757881328; hg19: chrX-106065358; API