2-165941111-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong

The NM_024753.5(TTC21B):c.626C>T(p.Pro209Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000799 in 1,613,836 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 Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000077 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:22

Conservation

PhyloP100: 8.08

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 links:

TTC21B-AS1 (HGNC:41115): (TTC21B antisense RNA 1)

TTC21B-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.903

PP5

Variant 2-165941111-G-A is Pathogenic according to our data. Variant chr2-165941111-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 30935.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-165941111-G-A is described in Lovd as [Likely_pathogenic]. Variant chr2-165941111-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC21B	NM_024753.5 link	c.626C>T	p.Pro209Leu	missense_variant	Exon 6 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.626C>T	p.Pro209Leu	missense_variant	Exon 6 of 29	1	NM_024753.5	ENSP00000243344.7		Q7Z4L5-1

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152104

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.00144

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000127

AC:

AN:

251118

Hom.:

AF XY:

0.000140

AC XY:

AN XY:

135698

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.000319

Gnomad ASJ exome

AF:

0.000794

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000881

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.0000766

AC:

112

AN:

1461614

Hom.:

Cov.:

AF XY:

0.0000756

AC XY:

AN XY:

727108

show subpopulations

Gnomad4 AFR exome

AF:

0.0000598

Gnomad4 AMR exome

AF:

0.000403

Gnomad4 ASJ exome

AF:

0.000689

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000522

Gnomad4 OTH exome

AF:

0.000215

GnomAD4 genome

AF:

0.000112

AC:

AN:

152222

Hom.:

Cov.:

AF XY:

0.000134

AC XY:

AN XY:

74428

show subpopulations

Gnomad4 AFR

AF:

0.0000722

Gnomad4 AMR

AF:

0.000262

Gnomad4 ASJ

AF:

0.00144

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000381

Hom.:

Bravo

AF:

0.000144

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000659

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000119

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:22

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:6

Sep 16, 2018

Gharavi Laboratory, Columbia University

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Apr 25, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Published functional studies demonstrate a damaging effect (Huynh Cong et al., 2014); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 24876116, 21258341, 29127259, 31456290, 32714622, 33599192, 34426522, 33712733, 31589614, 33226606, 33547761, 33532864, 26940125) -

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 24, 2019

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nephronophthisis 12

Pathogenic:6

Jun 26, 2017

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

Previously reported homozygous missense mutation (p.P209L) in the TTC21B gene in seven families with FSGS (PMID: 26940125). -

Mar 01, 2011

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Genomics And Bioinformatics Analysis Resource, Columbia University

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Dec 01, 2022

Eurofins-Biomnis

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 01, 2015

Equipe Genetique des Anomalies du Developpement, Université de Bourgogne

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 01, 2020

Molecular Biology Laboratory, Fundació Puigvert

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Nephrotic syndrome

Pathogenic:2

Nov 10, 2017

Yale Center for Mendelian Genomics, Yale University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

May 03, 2018

Sydney Genome Diagnostics, Children's Hospital Westmead

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This patient is homozygous for a known pathogenic variant, c.626C>T p.(Pro209Leu), in the TTC21B gene. This variant (dbSNP: rs140511594), in the homozygous state, has been previously reported in patients with nephronophthisis and focal segmental glomerulosclerosis (FSGS) (Davis et al 2011 Nat Genet 43:189-196; Cong et al 2014 J Am Soc Nephrol 25:2435-2443; Bullich et al 2017 Nephrol Dial Transplant 32:151-156). Bullich et al 2017 also reported hypertension in some patients homozygous for p.(Pro209Leu). This variant was found in patients of North Africian or Portuguese descent. Functional studies showed the p.Pro209Leu variant partially altered cilia structure, cell migration and cytoskeleton suggesting a hypomorphic allele (Davis et al 2011; Cong et al 2014; Bullich et al 2017). This variant is considered to be pathogenic according to the ACMG guidelines. -

Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12

Pathogenic:1

Mar 15, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Pathogenic:1

Dec 02, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 209 of the TTC21B protein (p.Pro209Leu). This variant is present in population databases (rs140511594, gnomAD 0.08%). This missense change has been observed in individual(s) with focal segmental glomerulosclerosis and nephronophthisis (PMID: 21258341, 24876116). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 30935). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on TTC21B protein function. Experimental studies have shown that this missense change affects TTC21B function (PMID: 21258341, 24876116). For these reasons, this variant has been classified as Pathogenic. -

See cases

Pathogenic:1

May 10, 2021

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ACMG classification criteria: PS3, PM3, PP1, PP3 -

TTC21B-related disorder

Pathogenic:1

Aug 30, 2024

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The TTC21B c.626C>T variant is predicted to result in the amino acid substitution p.Pro209Leu. This variant was reported in the homozygous or compound heterozygous state in multiple individuals with nephronophthisis or focal segmental glomerulosclerosis (FSGS) (Davis et al. 2011. PubMed ID: 21258341; Bullich et al. 2017. PubMed ID: 26940125; Cong et al. 2014. PubMed ID: 24876116). This variant is reported in 0.077% of alleles in individuals of Ashkenazi Jewish descent in gnomAD and has been interpreted in ClinVar as pathogenic/likely pathogenic by multiple submitters (https://preview.ncbi.nlm.nih.gov/clinvar/variation/30935/). This variant is interpreted as pathogenic. -

Finnish congenital nephrotic syndrome

Pathogenic:1

Nov 21, 2018

Bioscientia Institut fuer Medizinische Diagnostik GmbH, Sonic Healthcare

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Renal dysplasia and retinal aplasia

Pathogenic:1

Jun 23, 2019

Sharon lab, Hadassah-Hebrew University Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Retinal dystrophy

Pathogenic:1

Sep 22, 2017

Blueprint Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Infantile nephronophthisis

Pathogenic:1

Jan 28, 2019

Center of Genomic medicine, Geneva, University Hospital of Geneva

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was identified in composite heterozygosity with another variant in the same gene in a female patient with nephronophtisis, retinopathy and suspected ciliopathy -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.29

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Pathogenic

0.30

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.57

Eigen

Pathogenic

0.90

Eigen_PC

Pathogenic

0.84

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

M_CAP

Uncertain

0.21

MetaRNN

Pathogenic

0.90

MetaSVM

Uncertain

0.35

MutationAssessor

Pathogenic

3.1

PrimateAI

Uncertain

0.61

PROVEAN

Pathogenic

-6.4

REVEL

Pathogenic

0.72

Sift

Uncertain

0.0080

Sift4G

Uncertain

0.043

Polyphen

1.0

Vest4

0.91

MVP

0.77

MPC

0.23

ClinPred

0.87

GERP RS

5.4

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.40

gMVP

0.58

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over