rs749225304

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_005993.5(TBCD):​c.1876G>A​(p.Ala626Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000806 in 1,612,534 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A626S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

TBCD
NM_005993.5 missense

Scores

2
12
5

Clinical Significance

Uncertain significance criteria provided, single submitter P:1U:1

Conservation

PhyloP100: 7.03

Publications

3 publications found
Variant links:
Genes affected
TBCD (HGNC:11581): (tubulin folding cofactor D) Cofactor D is one of four proteins (cofactors A, D, E, and C) involved in the pathway leading to correctly folded beta-tubulin from folding intermediates. Cofactors A and D are believed to play a role in capturing and stabilizing beta-tubulin intermediates in a quasi-native confirmation. Cofactor E binds to the cofactor D/beta-tubulin complex; interaction with cofactor C then causes the release of beta-tubulin polypeptides that are committed to the native state. [provided by RefSeq, Jul 2008]
TBCD Gene-Disease associations (from GenCC):
  • early-onset progressive diffuse brain atrophy-microcephaly-muscle weakness-optic atrophy syndrome
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.746

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TBCDNM_005993.5 linkc.1876G>A p.Ala626Thr missense_variant Exon 20 of 39 ENST00000355528.9 NP_005984.3 Q9BTW9-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TBCDENST00000355528.9 linkc.1876G>A p.Ala626Thr missense_variant Exon 20 of 39 1 NM_005993.5 ENSP00000347719.4 Q9BTW9-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152250
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:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.000478
GnomAD2 exomes
AF:
0.00000406
AC:
1
AN:
246440
AF XY:
0.00000748
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:
0.00
Gnomad NFE exome
AF:
0.00000894
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000822
AC:
12
AN:
1460284
Hom.:
0
Cov.:
32
AF XY:
0.00000551
AC XY:
4
AN XY:
726228
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33464
American (AMR)
AF:
0.00
AC:
0
AN:
44556
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26108
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39672
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85752
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53292
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.00000900
AC:
10
AN:
1111356
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60320
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.421
Heterozygous variant carriers
0
1
2
4
5
6
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:
0.00000657
AC:
1
AN:
152250
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74392
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41470
American (AMR)
AF:
0.00
AC:
0
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5194
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
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:
0.00
AC:
0
AN:
68044
Other (OTH)
AF:
0.000478
AC:
1
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
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:
0.0000151
ExAC
AF:
0.00000826
AC:
1

ClinVar

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

Submissions by phenotype

Early-onset progressive diffuse brain atrophy-microcephaly-muscle weakness-optic atrophy syndrome Pathogenic:1
Nov 16, 2016
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

not provided Uncertain:1
Jul 07, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 626 of the TBCD protein (p.Ala626Thr). 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. This missense change has been observed in individual(s) with TBCD-related conditions (PMID: 27666370). ClinVar contains an entry for this variant (Variation ID: 268174). 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: "Possibly Damaging"; Align-GVGD: "Class C0"). Experimental studies have shown that this missense change affects TBCD function (PMID: 27666370). 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
Uncertain
0.37
BayesDel_addAF
Uncertain
0.037
T
BayesDel_noAF
Benign
-0.19
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Benign
0.25
T;.;.;.;T;T;.;T;.;.;T
Eigen
Uncertain
0.51
Eigen_PC
Uncertain
0.43
FATHMM_MKL
Pathogenic
0.97
D
LIST_S2
Uncertain
0.96
D;D;D;D;D;D;D;D;D;D;D
M_CAP
Uncertain
0.094
D
MetaRNN
Pathogenic
0.75
D;D;D;D;D;D;D;D;D;D;D
MetaSVM
Uncertain
-0.038
T
MutationAssessor
Uncertain
2.8
M;.;.;.;.;.;.;.;.;.;.
PhyloP100
7.0
PrimateAI
Benign
0.39
T
PROVEAN
Uncertain
-3.4
D;.;.;.;.;.;.;.;.;.;.
REVEL
Uncertain
0.44
Sift
Benign
0.033
D;.;.;.;.;.;.;.;.;.;.
Sift4G
Uncertain
0.035
D;D;D;D;D;D;D;D;D;D;D
Polyphen
1.0
D;.;.;.;.;.;.;.;.;.;.
Vest4
0.68
MutPred
0.67
Loss of helix (P = 0.2022);Loss of helix (P = 0.2022);.;.;.;.;.;.;.;.;.;
MVP
0.81
MPC
0.89
ClinPred
0.97
D
GERP RS
5.2
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.28
gMVP
0.47
Mutation Taster
=11/89
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: rs749225304; hg19: chr17-80863883; COSMIC: COSV62804447; COSMIC: COSV62804447; API