rs771335558

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_024809.5(TCTN2):c.2066G>C(p.Trp689Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00000682 in 1,614,010 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

TCTN2
NM_024809.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 6.69

Publications

2 publications found

Variant links:

Genes affected

TCTN2 (HGNC:25774): (tectonic family member 2) This gene encodes a type I membrane protein that belongs to the tectonic family. Studies in mice suggest that this protein may be involved in hedgehog signaling, and essential for ciliogenesis. Mutations in this gene are associated with Meckel syndrome type 8. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2011]

TCTN2 Gene-Disease associations (from GenCC):

Joubert syndrome 24
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: ClinGen, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
Joubert syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Meckel syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

TCTN2 links:

ENSG00000255839 (HGNC:):

ENSG00000255839 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCTN2	NM_024809.5 link	c.2066G>C	p.Trp689Ser	missense_variant	Exon 18 of 18	ENST00000303372.7	NP_079085.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCTN2	ENST00000303372.7 link	c.2066G>C	p.Trp689Ser	missense_variant	Exon 18 of 18	1	NM_024809.5	ENSP00000304941.5

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152136

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000161

AC:

AN:

249056

AF XY:

0.00000742

show subpopulations

Gnomad AFR exome

AF:

0.000246

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000410

AC:

AN:

1461874

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727242

show subpopulations

African (AFR)

AF:

0.000149

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111994

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152136

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74320

show subpopulations

African (AFR)

AF:

0.000121

AC:

AN:

41426

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68012

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Jun 07, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.2066G>C (p.W689S) alteration is located in exon 18 (coding exon 18) of the TCTN2 gene. This alteration results from a G to C substitution at nucleotide position 2066, causing the tryptophan (W) at amino acid position 689 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Meckel syndrome, type 8;C4084841:Joubert syndrome 24

Uncertain:1

May 17, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Meckel-Gruber syndrome;C0431399:Joubert syndrome

Uncertain:1

Jul 30, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with serine, which is neutral and polar, at codon 689 of the TCTN2 protein (p.Trp689Ser). This variant is present in population databases (rs771335558, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with TCTN2-related conditions. ClinVar contains an entry for this variant (Variation ID: 461765). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.18

BayesDel_addAF

Uncertain

0.021

BayesDel_noAF

Uncertain

0.090

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.68

.;D

Eigen

Pathogenic

0.74

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.66

T;T

M_CAP

Uncertain

0.11

MetaRNN

Uncertain

0.74

D;D

MetaSVM

Uncertain

0.40

MutationAssessor

Uncertain

2.6

.;M

PhyloP100

6.7

PrimateAI

Benign

0.43

PROVEAN

Pathogenic

-6.1

D;D

REVEL

Pathogenic

0.65

Sift

Benign

0.19

T;T

Sift4G

Uncertain

0.0020

D;D

Polyphen

1.0

.;D

Vest4

0.58

MVP

0.98

MPC

0.70

ClinPred

0.88

GERP RS

5.7

Varity_R

0.53

gMVP

0.88

Mutation Taster

=43/57

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over