rs79746977

Variant summary

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

The NM_024753.5(TTC21B):​c.2500C>T​(p.Gln834*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000164 in 1,613,082 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 (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000092 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00017 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 stop_gained

Scores

5
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 8.09

Publications

9 publications found
Variant links:
Genes affected
TTC21B (HGNC:25660): (tetratricopeptide repeat domain 21B) This gene encodes a member of TTC21 family, containing several tetratricopeptide repeat (TPR) domains. This protein is localized to the cilium axoneme, and may play a role in retrograde intraflagellar transport in cilia. Mutations in this gene are associated with various ciliopathies, nephronophthisis 12, and asphyxiating thoracic dystrophy 4. [provided by RefSeq, Oct 2011]
TTC21B Gene-Disease associations (from GenCC):
  • nephronophthisis 12
    Inheritance: AD, AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae)
  • asphyxiating thoracic dystrophy 4
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • Jeune syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • nephronophthisis 2
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

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 undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PP5
Variant 2-165907746-G-A is Pathogenic according to our data. Variant chr2-165907746-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 446649.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_024753.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
TTC21B
NM_024753.5
MANE Select
c.2500C>Tp.Gln834*
stop_gained
Exon 19 of 29NP_079029.3

Ensembl Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
TTC21B
ENST00000243344.8
TSL:1 MANE Select
c.2500C>Tp.Gln834*
stop_gained
Exon 19 of 29ENSP00000243344.7
TTC21B
ENST00000679840.1
c.2500C>Tp.Gln834*
stop_gained
Exon 19 of 27ENSP00000505248.1
TTC21B
ENST00000679799.1
c.2500C>Tp.Gln834*
stop_gained
Exon 19 of 28ENSP00000505208.1

Frequencies

GnomAD3 genomes
AF:
0.0000920
AC:
14
AN:
152104
Hom.:
0
Cov.:
32
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:
0.000206
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000638
AC:
16
AN:
250924
AF XY:
0.0000664
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:
0.000141
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000172
AC:
251
AN:
1460860
Hom.:
0
Cov.:
30
AF XY:
0.000182
AC XY:
132
AN XY:
726776
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33456
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26118
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39584
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86226
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53050
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5762
European-Non Finnish (NFE)
AF:
0.000220
AC:
244
AN:
1111586
Other (OTH)
AF:
0.0000994
AC:
6
AN:
60358
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.440
Heterozygous variant carriers
0
12
24
35
47
59
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:
0.0000920
AC:
14
AN:
152222
Hom.:
0
Cov.:
32
AF XY:
0.0000672
AC XY:
5
AN XY:
74434
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41524
American (AMR)
AF:
0.00
AC:
0
AN:
15300
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5174
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4824
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10594
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.000206
AC:
14
AN:
68014
Other (OTH)
AF:
0.00
AC:
0
AN:
2114
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.529
Heterozygous variant carriers
0
1
3
4
6
7
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:
0.000115
Hom.:
0
Bravo
AF:
0.0000718
ExAC
AF:
0.0000330
AC:
4
EpiCase
AF:
0.0000545
EpiControl
AF:
0.000119

ClinVar

ClinVar submissions as Germline

Significance:Pathogenic
Revision:criteria provided, multiple submitters, no conflicts
View on ClinVar
Pathogenic
VUS
Benign
Condition
2
-
-
Short-rib thoracic dysplasia 6 with or without polydactyly (2)
1
-
-
Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12 (1)
1
-
-
Jeune thoracic dystrophy;C0687120:Nephronophthisis (1)
1
-
-
not provided (1)
1
-
-
TTC21B-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.47
D
BayesDel_noAF
Pathogenic
0.63
CADD
Pathogenic
43
DANN
Uncertain
1.0
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.98
FATHMM_MKL
Pathogenic
0.99
D
PhyloP100
8.1
Vest4
0.28
GERP RS
5.4
Mutation Taster
=3/197
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.36
Details are displayed if max score is > 0.2
DS_AL_spliceai
0.36
Position offset: 38

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs79746977; hg19: chr2-166764256; API