2-165912609-C-T

Position:

chr2-165912609-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBP6

The NM_024753.5(TTC21B):c.2227G>A(p.Val743Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000124 in 1,613,992 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00058 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000076 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:3

Conservation

PhyloP100: 3.15

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.0133678615).

BP6

Variant 2-165912609-C-T is Benign according to our data. Variant chr2-165912609-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 331829.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=4}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTC21B	NM_024753.5 linkuse as main transcript	c.2227G>A	p.Val743Ile	missense_variant	17/29	ENST00000243344.8	NP_079029.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTC21B	ENST00000243344.8 linkuse as main transcript	c.2227G>A	p.Val743Ile	missense_variant	17/29	1	NM_024753.5	ENSP00000243344	P1	Q7Z4L5-1

Frequencies

GnomAD3 genomes

AF:

0.000578

AC:

AN:

152152

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00157

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00124

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:

0.0000294

Gnomad OTH

AF:

0.000955

GnomAD3 exomes

AF:

0.000175

AC:

AN:

251326

Hom.:

AF XY:

0.000133

AC XY:

AN XY:

135830

show subpopulations

Gnomad AFR exome

AF:

0.00191

Gnomad AMR exome

AF:

0.000202

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:

0.0000352

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.0000759

AC:

111

AN:

1461722

Hom.:

Cov.:

AF XY:

0.0000674

AC XY:

AN XY:

727164

show subpopulations

Gnomad4 AFR exome

AF:

0.00143

Gnomad4 AMR exome

AF:

0.000268

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000333

Gnomad4 OTH exome

AF:

0.000182

GnomAD4 genome

AF:

0.000584

AC:

AN:

152270

Hom.:

Cov.:

AF XY:

0.000564

AC XY:

AN XY:

74444

show subpopulations

Gnomad4 AFR

AF:

0.00159

Gnomad4 AMR

AF:

0.00124

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.000945

Alfa

AF:

0.000124

Hom.:

Bravo

AF:

0.000820

ESP6500AA

AF:

0.000908

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000206

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 28, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Oct 24, 2017	- -

Asphyxiating thoracic dystrophy 4

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 22, 2021

The c.2227G>A (p.V743I) alteration is located in exon 17 (coding exon 17) of the TTC21B gene. This alteration results from a G to A substitution at nucleotide position 2227, causing the valine (V) at amino acid position 743 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Nephronophthisis 12

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 24, 2023

- -

TTC21B-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jul 30, 2024

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.078

BayesDel_addAF

Benign

-0.50

BayesDel_noAF

Benign

-0.49

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.24

Eigen

Benign

-0.55

Eigen_PC

Benign

-0.40

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.67

M_CAP

Benign

0.015

MetaRNN

Benign

0.013

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.85

MutationTaster

Benign

0.65

PrimateAI

Benign

0.37

PROVEAN

Benign

-0.86

REVEL

Benign

0.031

Sift

Benign

0.040

Sift4G

Uncertain

0.032

Polyphen

0.0030

Vest4

0.26

MVP

0.27

MPC

0.028

ClinPred

0.027

GERP RS

3.4

Varity_R

0.12

gMVP

0.16

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