2-165941053-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_024753.5(TTC21B):​c.684G>A​(p.Trp228Ter) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,644 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 Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 stop_gained

Scores

5
1
1

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 7.91
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-AS1 (HGNC:41115): (TTC21B antisense RNA 1)

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 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 2-165941053-C-T is Pathogenic according to our data. Variant chr2-165941053-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 216125.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
TTC21BNM_024753.5 linkuse as main transcriptc.684G>A p.Trp228Ter stop_gained 6/29 ENST00000243344.8
TTC21B-AS1NR_038983.1 linkuse as main transcriptn.277-6144C>T intron_variant, non_coding_transcript_variant

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
TTC21BENST00000243344.8 linkuse as main transcriptc.684G>A p.Trp228Ter stop_gained 6/291 NM_024753.5 P1Q7Z4L5-1
TTC21B-AS1ENST00000440322.5 linkuse as main transcriptn.221-6144C>T intron_variant, non_coding_transcript_variant 4

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD3 exomes
AF:
0.00000796
AC:
2
AN:
251284
Hom.:
0
AF XY:
0.0000147
AC XY:
2
AN XY:
135804
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:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461644
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
727124
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:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
8.99e-7
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
33
ExAC
AF:
0.00000824
AC:
1
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Jeune thoracic dystrophy;C0687120:Nephronophthisis Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpAug 10, 2023This variant is present in population databases (rs777162250, gnomAD 0.002%). This variant has not been reported in the literature in individuals affected with TTC21B-related conditions. ClinVar contains an entry for this variant (Variation ID: 216125). For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Trp228*) 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). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.61
D
BayesDel_noAF
Pathogenic
0.66
CADD
Pathogenic
37
DANN
Uncertain
1.0
Eigen
Pathogenic
0.96
Eigen_PC
Pathogenic
0.84
FATHMM_MKL
Pathogenic
1.0
D
MutationTaster
Benign
1.0
A
Vest4
0.38
GERP RS
5.2
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.090
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.

Other links and lift over

dbSNP: rs777162250; hg19: chr2-166797563; API