2-165941072-T-A

Variant names:

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_024753.5(TTC21B):c.665A>T(p.Gln222Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00216 in 1,613,962 control chromosomes in the GnomAD database, including 80 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.012 ( 39 hom., cov: 33)

Exomes 𝑓: 0.0011 ( 41 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:14

Conservation

PhyloP100: 4.04

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 Benign. Variant got -20 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.0083556175).

BP6

Variant 2-165941072-T-A is Benign according to our data. Variant chr2-165941072-T-A is described in ClinVar as [Likely_benign]. Clinvar id is 130658.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-165941072-T-A is described in Lovd as [Benign].

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0119 (1819/152300) while in subpopulation AFR AF= 0.0415 (1726/41552). AF 95% confidence interval is 0.0399. There are 39 homozygotes in gnomad4. There are 832 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

BS2

High Homozygotes in GnomAd4 at 39 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC21B	NM_024753.5 link	c.665A>T	p.Gln222Leu	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.665A>T	p.Gln222Leu	missense_variant	Exon 6 of 29	1	NM_024753.5	ENSP00000243344.7		Q7Z4L5-1

Frequencies

GnomAD3 genomes

AF:

0.0119

AC:

1817

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0416

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00491

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00670

GnomAD3 exomes

AF:

0.00299

AC:

752

AN:

251252

Hom.:

AF XY:

0.00207

AC XY:

281

AN XY:

135786

show subpopulations

Gnomad AFR exome

AF:

0.0403

Gnomad AMR exome

AF:

0.00220

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000968

Gnomad OTH exome

AF:

0.00163

GnomAD4 exome

AF:

0.00114

AC:

1661

AN:

1461662

Hom.:

Cov.:

AF XY:

0.000959

AC XY:

697

AN XY:

727138

show subpopulations

Gnomad4 AFR exome

AF:

0.0398

Gnomad4 AMR exome

AF:

0.00266

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000513

Gnomad4 OTH exome

AF:

0.00242

GnomAD4 genome

AF:

0.0119

AC:

1819

AN:

152300

Hom.:

Cov.:

AF XY:

0.0112

AC XY:

832

AN XY:

74480

show subpopulations

Gnomad4 AFR

AF:

0.0415

Gnomad4 AMR

AF:

0.00490

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00663

Alfa

AF:

0.000737

Hom.:

Bravo

AF:

0.0139

ESP6500AA

AF:

0.0388

AC:

171

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00369

AC:

448

Asia WGS

AF:

0.00173

AC:

AN:

3478

EpiCase

AF:

0.000109

EpiControl

AF:

0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:14

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:5

Likely benign, no assertion criteria provided	clinical testing	Genetic Services Laboratory, University of Chicago	-	Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -
Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Sep 04, 2014	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 20, 2016	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -

not provided

Benign:4

Benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Oct 01, 2022	TTC21B: BP4, BS1, BS2 -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Jun 28, 2023	- -
Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Likely benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -

Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12

Benign:1

Benign, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 21, 2021

- -

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 03, 2025

- -

Asphyxiating thoracic dystrophy 4

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Nephronophthisis 12

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Connective tissue disorder

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

Aug 01, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.50

BayesDel_noAF

Benign

-0.46

CADD

Benign

DANN

Benign

0.96

DEOGEN2

Benign

0.15

Eigen

Benign

-0.078

Eigen_PC

Benign

0.13

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.81

MetaRNN

Benign

0.0084

MetaSVM

Benign

-1.1

MutationAssessor

Benign

1.4

PrimateAI

Benign

0.48

PROVEAN

Benign

-0.75

REVEL

Benign

0.087

Sift

Benign

0.68

Sift4G

Benign

0.66

Polyphen

0.034

Vest4

0.28

MVP

0.35

MPC

0.031

ClinPred

0.0099

GERP RS

5.4

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.11

gMVP

0.42

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