rs77106136

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_024753.5(TTC21B):​c.1870A>G​(p.Ile624Val) variant causes a missense change. The variant allele was found at a frequency of 0.00113 in 1,614,190 control chromosomes in the GnomAD database, including 21 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

Frequency

Genomes: 𝑓 0.0056 ( 9 hom., cov: 32)
Exomes 𝑓: 0.00066 ( 12 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

1
17

Clinical Significance

Benign criteria provided, multiple submitters, no conflicts B:8

Conservation

PhyloP100: 4.88

Publications

5 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: Benign. The variant received -20 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.0028590262).
BP6
Variant 2-165917286-T-C is Benign according to our data. Variant chr2-165917286-T-C is described in ClinVar as [Benign]. Clinvar id is 331831.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
BS1
Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.0056 (853/152332) while in subpopulation AFR AF = 0.0197 (818/41574). AF 95% confidence interval is 0.0186. There are 9 homozygotes in GnomAd4. There are 414 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
BS2
High Homozygotes in GnomAd4 at 9 AR,AD gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTC21BNM_024753.5 linkc.1870A>G p.Ile624Val missense_variant Exon 14 of 29 ENST00000243344.8 NP_079029.3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTC21BENST00000243344.8 linkc.1870A>G p.Ile624Val missense_variant Exon 14 of 29 1 NM_024753.5 ENSP00000243344.7 Q7Z4L5-1

Frequencies

GnomAD3 genomes
AF:
0.00561
AC:
854
AN:
152214
Hom.:
9
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0198
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00137
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.00382
GnomAD2 exomes
AF:
0.00157
AC:
395
AN:
251386
AF XY:
0.00126
show subpopulations
Gnomad AFR exome
AF:
0.0204
Gnomad AMR exome
AF:
0.00147
Gnomad ASJ exome
AF:
0.0000992
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000352
Gnomad OTH exome
AF:
0.000978
GnomAD4 exome
AF:
0.000665
AC:
972
AN:
1461858
Hom.:
12
Cov.:
31
AF XY:
0.000575
AC XY:
418
AN XY:
727226
show subpopulations
African (AFR)
AF:
0.0230
AC:
771
AN:
33480
American (AMR)
AF:
0.00152
AC:
68
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.0000765
AC:
2
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39682
South Asian (SAS)
AF:
0.0000232
AC:
2
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00191
AC:
11
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000432
AC:
48
AN:
1112002
Other (OTH)
AF:
0.00116
AC:
70
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.483
Heterozygous variant carriers
0
57
114
170
227
284
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
28
56
84
112
140
<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:
0.00560
AC:
853
AN:
152332
Hom.:
9
Cov.:
32
AF XY:
0.00556
AC XY:
414
AN XY:
74494
show subpopulations
African (AFR)
AF:
0.0197
AC:
818
AN:
41574
American (AMR)
AF:
0.00137
AC:
21
AN:
15298
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5196
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000735
AC:
5
AN:
68024
Other (OTH)
AF:
0.00378
AC:
8
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.502
Heterozygous variant carriers
0
40
80
120
160
200
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Genome Hom
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
Alfa
AF:
0.00252
Hom.:
14
Bravo
AF:
0.00651
ESP6500AA
AF:
0.0227
AC:
100
ESP6500EA
AF:
0.00
AC:
0
ExAC
AF:
0.00180
AC:
219
Asia WGS
AF:
0.000577
AC:
2
AN:
3478
EpiCase
AF:
0.000273
EpiControl
AF:
0.000119

ClinVar

Significance: Benign
Submissions summary: Benign:8
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Benign:4
-
Genome Diagnostics Laboratory, University Medical Center Utrecht
Significance:Likely benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Nov 06, 2023
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jul 30, 2018
GeneDx
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 21258341) -

-
Breakthrough Genomics, Breakthrough Genomics
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:not provided

- -

not specified Benign:1
-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance:Benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Jeune thoracic dystrophy;C0687120:Nephronophthisis Benign:1
Feb 03, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Asphyxiating thoracic dystrophy 4 Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Nephronophthisis 12 Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.061
BayesDel_addAF
Benign
-0.55
T
BayesDel_noAF
Benign
-0.55
CADD
Benign
12
DANN
Benign
0.29
DEOGEN2
Benign
0.058
T
Eigen
Benign
-0.84
Eigen_PC
Benign
-0.57
FATHMM_MKL
Benign
0.29
N
LIST_S2
Benign
0.74
T
MetaRNN
Benign
0.0029
T
MetaSVM
Benign
-0.93
T
MutationAssessor
Benign
-1.8
N
PhyloP100
4.9
PrimateAI
Benign
0.26
T
PROVEAN
Benign
0.79
N
REVEL
Uncertain
0.29
Sift
Benign
1.0
T
Sift4G
Benign
1.0
T
Polyphen
0.0
B
Vest4
0.076
MVP
0.32
MPC
0.027
ClinPred
0.0045
T
GERP RS
4.9
Varity_R
0.037
gMVP
0.16
Mutation Taster
=93/7
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
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: rs77106136; hg19: chr2-166773796; API