2-165917310-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_024753.5(TTC21B):c.1846C>T(p.Arg616Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00294 in 1,614,122 control chromosomes in the GnomAD database, including 33 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R616H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0028 ( 2 hom., cov: 32)

Exomes 𝑓: 0.0030 ( 31 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:8

Conservation

PhyloP100: 4.88

Publications

17 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):

asphyxiating thoracic dystrophy 4
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
nephronophthisis 12
Inheritance: AR, AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
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 -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.00830844).

BP6

Variant 2-165917310-G-A is Benign according to our data. Variant chr2-165917310-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 130651.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.0028 (426/152272) while in subpopulation SAS AF = 0.0147 (71/4822). AF 95% confidence interval is 0.012. There are 2 homozygotes in GnomAd4. There are 212 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High Homozygotes in GnomAd4 at 2 AR,AD gene

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC21B	NM_024753.5	MANE Select	c.1846C>T	p.Arg616Cys	missense	Exon 14 of 29	NP_079029.3

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTC21B	ENST00000243344.8	TSL:1 MANE Select	c.1846C>T	p.Arg616Cys	missense	Exon 14 of 29	ENSP00000243344.7	Q7Z4L5-1
TTC21B	ENST00000679840.1		c.1846C>T	p.Arg616Cys	missense	Exon 14 of 27	ENSP00000505248.1	A0A7P0T8P4
TTC21B	ENST00000679799.1		c.1846C>T	p.Arg616Cys	missense	Exon 14 of 28	ENSP00000505208.1	A0A494C0N4

Frequencies

GnomAD3 genomes

AF:

0.00279

AC:

424

AN:

152152

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000434

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00491

Gnomad ASJ

AF:

0.0101

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.0143

Gnomad FIN

AF:

0.000471

Gnomad MID

AF:

0.0191

Gnomad NFE

AF:

0.00304

Gnomad OTH

AF:

0.00430

GnomAD2 exomes

AF:

0.00421

AC:

1059

AN:

251366

AF XY:

0.00515

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00385

Gnomad ASJ exome

AF:

0.00933

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000462

Gnomad NFE exome

AF:

0.00288

Gnomad OTH exome

AF:

0.00669

GnomAD4 exome

AF:

0.00296

AC:

4326

AN:

1461850

Hom.:

Cov.:

AF XY:

0.00345

AC XY:

2510

AN XY:

727224

show subpopulations

African (AFR)

AF:

0.000358

AC:

AN:

33480

American (AMR)

AF:

0.00387

AC:

173

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00953

AC:

249

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39682

South Asian (SAS)

AF:

0.0142

AC:

1226

AN:

86254

European-Finnish (FIN)

AF:

0.000505

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.0184

AC:

106

AN:

5766

European-Non Finnish (NFE)

AF:

0.00204

AC:

2271

AN:

1111996

Other (OTH)

AF:

0.00434

AC:

262

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

254

507

761

1014

1268

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

188

282

376

470

<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:

0.00280

AC:

426

AN:

152272

Hom.:

Cov.:

AF XY:

0.00285

AC XY:

212

AN XY:

74446

show subpopulations

African (AFR)

AF:

0.000433

AC:

AN:

41550

American (AMR)

AF:

0.00490

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.0101

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.0147

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.000471

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.0204

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00303

AC:

206

AN:

68026

Other (OTH)

AF:

0.00473

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

115

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:

0.00286

Hom.:

Bravo

AF:

0.00255

TwinsUK

AF:

0.00243

AC:

ALSPAC

AF:

0.00104

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.00256

AC:

ExAC

AF:

0.00427

AC:

518

Asia WGS

AF:

0.00318

AC:

AN:

3478

EpiCase

AF:

0.00523

EpiControl

AF:

0.00510

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (3)

not specified (2)

Asphyxiating thoracic dystrophy 4 (1)

Connective tissue disorder (1)

Jeune thoracic dystrophy;C0687120:Nephronophthisis (1)

Nephronophthisis 12 (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.36

BayesDel_noAF

Benign

-0.28

CADD

Benign

(source)

DANN

Benign

0.96

DEOGEN2

Uncertain

0.49

Eigen

Benign

-0.21

Eigen_PC

Benign

-0.11

FATHMM_MKL

Uncertain

0.93

LIST_S2

Benign

0.82

MetaRNN

Benign

0.0083

MetaSVM

Benign

-0.64

MutationAssessor

Uncertain

2.2

PhyloP100

4.9

PrimateAI

Benign

0.43

PROVEAN

Pathogenic

-5.3

REVEL

Uncertain

0.30

Sift

Benign

0.064

Sift4G

Uncertain

0.050

Polyphen

0.20

Vest4

0.35

MVP

0.55

MPC

0.043

ClinPred

0.094

GERP RS

4.9

Varity_R

0.30

gMVP

0.39

Mutation Taster

=84/16

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over