rs148222901

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_024753.5(TTC21B):c.2255A>G(p.Asn752Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000787 in 1,614,102 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000047 ( 0 hom. )

Consequence

TTC21B
NM_024753.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1

Conservation

PhyloP100: 3.19

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 Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.2571214).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTC21B	NM_024753.5 linkuse as main transcript	c.2255A>G	p.Asn752Ser	missense_variant	17/29	ENST00000243344.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTC21B	ENST00000243344.8 linkuse as main transcript	c.2255A>G	p.Asn752Ser	missense_variant	17/29	1	NM_024753.5	P1	Q7Z4L5-1

Frequencies

GnomAD3 genomes

AF:

0.000388

AC:

AN:

152152

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00125

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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:

0.00

Gnomad OTH

AF:

0.000956

GnomAD3 exomes

AF:

0.0000835

AC:

AN:

251376

Hom.:

AF XY:

0.0000736

AC XY:

AN XY:

135862

show subpopulations

Gnomad AFR exome

AF:

0.000984

Gnomad AMR exome

AF:

0.000116

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:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000465

AC:

AN:

1461832

Hom.:

Cov.:

AF XY:

0.0000399

AC XY:

AN XY:

727220

show subpopulations

Gnomad4 AFR exome

AF:

0.00161

Gnomad4 AMR exome

AF:

0.0000671

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:

0.000166

GnomAD4 genome

AF:

0.000387

AC:

AN:

152270

Hom.:

Cov.:

AF XY:

0.000416

AC XY:

AN XY:

74442

show subpopulations

Gnomad4 AFR

AF:

0.00125

Gnomad4 AMR

AF:

0.000327

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000946

Alfa

AF:

0.000263

Hom.:

Bravo

AF:

0.000427

ESP6500AA

AF:

0.000681

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000824

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 19, 2022

- -

TTC21B-related condition

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Dec 14, 2023

The TTC21B c.2255A>G variant is predicted to result in the amino acid substitution p.Asn752Ser. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.11% of alleles in individuals of African descent in gnomAD. Although we suspect this variant could be benign, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 10, 2022

The c.2255A>G (p.N752S) alteration is located in exon 17 (coding exon 17) of the TTC21B gene. This alteration results from a A to G substitution at nucleotide position 2255, causing the asparagine (N) at amino acid position 752 to be replaced by a serine (S). 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

Baylor Genetics

Jun 26, 2018

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Jeune thoracic dystrophy;C0687120:Nephronophthisis

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 19, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Benign

-0.49

BayesDel_noAF

Benign

-0.51

Cadd

Benign

Dann

Uncertain

1.0

DEOGEN2

Uncertain

0.62

Eigen

Uncertain

0.38

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.91

M_CAP

Benign

0.041

MetaRNN

Benign

0.26

MetaSVM

Benign

-0.59

MutationAssessor

Uncertain

2.2

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.56

PROVEAN

Pathogenic

-4.5

REVEL

Uncertain

0.35

Sift

Benign

0.052

Sift4G

Uncertain

0.051

Polyphen

0.97

Vest4

0.32

MVP

0.47

MPC

0.093

ClinPred

0.25

GERP RS

4.0

Varity_R

0.25

gMVP

0.34

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