2-165919379-G-C

Variant names:

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.1571C>G(p.Ser524Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00062 in 1,614,088 control chromosomes in the GnomAD database, including 6 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0033 ( 3 hom., cov: 32)

Exomes 𝑓: 0.00034 ( 3 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:7

Conservation

PhyloP100: 6.88

Publications

2 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

TTC21B links:

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=0.010604382).

BP6

Variant 2-165919379-G-C is Benign according to our data. Variant chr2-165919379-G-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 241575.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 = 0.00335 (510/152282) while in subpopulation AFR AF = 0.0112 (467/41556). AF 95% confidence interval is 0.0104. There are 3 homozygotes in GnomAd4. There are 214 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High Homozygotes in GnomAd4 at 3 AR,AD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC21B	NM_024753.5 link	c.1571C>G	p.Ser524Cys	missense_variant	Exon 13 of 29	ENST00000243344.8	NP_079029.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC21B	ENST00000243344.8 link	c.1571C>G	p.Ser524Cys	missense_variant	Exon 13 of 29	1	NM_024753.5	ENSP00000243344.7

Frequencies

GnomAD3 genomes

AF:

0.00327

AC:

497

AN:

152164

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0110

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00223

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:

0.00431

GnomAD2 exomes

AF:

0.000832

AC:

209

AN:

251258

AF XY:

0.000545

show subpopulations

Gnomad AFR exome

AF:

0.0120

Gnomad AMR exome

AF:

0.000318

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000490

GnomAD4 exome

AF:

0.000335

AC:

490

AN:

1461806

Hom.:

Cov.:

AF XY:

0.000298

AC XY:

217

AN XY:

727206

show subpopulations

African (AFR)

AF:

0.0123

AC:

411

AN:

33474

American (AMR)

AF:

0.000604

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39676

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111972

Other (OTH)

AF:

0.000795

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

Heterozygous variant carriers

114

142

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.00335

AC:

510

AN:

152282

Hom.:

Cov.:

AF XY:

0.00287

AC XY:

214

AN XY:

74470

show subpopulations

African (AFR)

AF:

0.0112

AC:

467

AN:

41556

American (AMR)

AF:

0.00222

AC:

AN:

15298

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68020

Other (OTH)

AF:

0.00426

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.507

Heterozygous variant carriers

102

127

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

<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:

0.000218

Hom.:

Bravo

AF:

0.00395

ESP6500AA

AF:

0.00999

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000939

AC:

114

Asia WGS

AF:

0.00144

AC:

AN:

3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:3

Feb 24, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Dec 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTC21B: BP4, BS1, BS2

Sep 08, 2021

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not specified

Benign:1

PreventionGenetics, part of Exact Sciences

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Benign:1

Jan 20, 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 12, 2018

Illumina Laboratory Services, Illumina

Significance:Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease.

Nephronophthisis 12

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.099

BayesDel_addAF

Benign

-0.29

BayesDel_noAF

Benign

-0.19

CADD

Uncertain

(source)

DANN

Uncertain

0.98

DEOGEN2

Uncertain

0.56

Eigen

Uncertain

0.38

Eigen_PC

Uncertain

0.31

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.72

MetaRNN

Benign

0.011

MetaSVM

Uncertain

0.069

MutationAssessor

Uncertain

2.5

PhyloP100

6.9

PrimateAI

Benign

0.44

PROVEAN

Uncertain

-2.6

REVEL

Uncertain

0.55

Sift

Uncertain

0.029

Sift4G

Uncertain

0.026

Vest4

0.43

ClinPred

0.057

GERP RS

4.7

Varity_R

0.25

gMVP

0.30

Mutation Taster

=53/47

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over