Variant rs775836730 details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_024753.5(TTC21B):c.1320del(p.Phe440LeufsTer4) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000663 in 1,612,878 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000071 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 3.10

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 Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-165929200-CA-C is Pathogenic according to our data. Variant chr2-165929200-CA-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 446650.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-165929200-CA-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTC21B	NM_024753.5 linkuse as main transcript	c.1320del	p.Phe440LeufsTer4	frameshift_variant	11/29	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.1320del	p.Phe440LeufsTer4	frameshift_variant	11/29	1	NM_024753.5	ENSP00000243344	P1	Q7Z4L5-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152050

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000589

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000399

AC:

AN:

250524

Hom.:

AF XY:

0.0000369

AC XY:

AN XY:

135428

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

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:

0.0000884

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000705

AC:

103

AN:

1460828

Hom.:

Cov.:

AF XY:

0.0000633

AC XY:

AN XY:

726712

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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:

0.0000828

Gnomad4 OTH exome

AF:

0.000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152050

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74264

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000589

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000529

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Type IV short rib polydactyly syndrome

Pathogenic:2

Pathogenic, no assertion criteria provided	research	Dan Cohn Lab, University Of California Los Angeles	Jun 01, 2017	- -
Likely pathogenic, no assertion criteria provided	research	University of Washington Center for Mendelian Genomics, University of Washington	-	- -

Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Jan 18, 2022

- -

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 17, 2023

This sequence change creates a premature translational stop signal (p.Phe440Leufs*4) in the TTC21B gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TTC21B are known to be pathogenic (PMID: 18327258, 21068128, 21258341, 23559409, 24876116, 25492405, 27491411, 29068549). This variant is present in population databases (rs775836730, gnomAD 0.009%). This premature translational stop signal has been observed in individual(s) with short-rib polydactyly syndrome type IV (PMID: 29068549). ClinVar contains an entry for this variant (Variation ID: 446650). For these reasons, this variant has been classified as Pathogenic. -

Retinal dystrophy

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Blueprint Genetics

Sep 22, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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