rs151318349

Positions:

chr12-123688062-A-G

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBS1_Supporting

The NM_024809.5(TCTN2):c.776A>G(p.Gln259Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00111 in 1,614,132 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/21 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 0.00069 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0012 ( 1 hom. )

Consequence

TCTN2
NM_024809.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 0.0340

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 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=0.010862678).

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000689 (105/152342) while in subpopulation NFE AF= 0.00119 (81/68034). AF 95% confidence interval is 0.000981. There are 0 homozygotes in gnomad4. There are 41 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TCTN2	NM_024809.5 linkuse as main transcript	c.776A>G	p.Gln259Arg	missense_variant	7/18	ENST00000303372.7	NP_079085.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TCTN2	ENST00000303372.7 linkuse as main transcript	c.776A>G	p.Gln259Arg	missense_variant	7/18	1	NM_024809.5	ENSP00000304941	P4	Q96GX1-1

Frequencies

GnomAD3 genomes

AF:

0.000690

AC:

105

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000386

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000458

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:

0.00119

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.000553

AC:

139

AN:

251462

Hom.:

AF XY:

0.000596

AC XY:

AN XY:

135908

show subpopulations

Gnomad AFR exome

AF:

0.000185

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:

0.00113

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00116

AC:

1689

AN:

1461790

Hom.:

Cov.:

AF XY:

0.00113

AC XY:

824

AN XY:

727198

show subpopulations

Gnomad4 AFR exome

AF:

0.000179

Gnomad4 AMR exome

AF:

0.000201

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000696

Gnomad4 FIN exome

AF:

0.0000375

Gnomad4 NFE exome

AF:

0.00144

Gnomad4 OTH exome

AF:

0.00111

GnomAD4 genome

AF:

0.000689

AC:

105

AN:

152342

Hom.:

Cov.:

AF XY:

0.000550

AC XY:

AN XY:

74500

show subpopulations

Gnomad4 AFR

AF:

0.000385

Gnomad4 AMR

AF:

0.000458

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00119

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.00106

Hom.:

Bravo

AF:

0.000725

TwinsUK

AF:

0.00108

AC:

ALSPAC

AF:

0.00130

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000581

AC:

ExAC

AF:

0.000552

AC:

EpiCase

AF:

0.00169

EpiControl

AF:

0.00113

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Meckel-Gruber syndrome;C0431399:Familial aplasia of the vermis

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 15, 2024

This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 259 of the TCTN2 protein (p.Gln259Arg). This variant is present in population databases (rs151318349, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. 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: 307553). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TCTN2 protein function with a negative predictive value of 80%. 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. -

Joubert syndrome 24

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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. -

Meckel syndrome, type 8

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

Inborn genetic diseases

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 18, 2022

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.070

BayesDel_addAF

Benign

-0.50

BayesDel_noAF

Benign

-0.53

CADD

Benign

0.95

DANN

Benign

0.65

DEOGEN2

Benign

0.27

.;T

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.30

LIST_S2

Benign

0.31

T;T

M_CAP

Benign

0.019

MetaRNN

Benign

0.011

T;T

MetaSVM

Benign

-0.81

MutationAssessor

Benign

1.6

.;L

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.28

PROVEAN

Benign

-0.77

N;N

REVEL

Benign

0.10

Sift

Benign

0.83

T;T

Sift4G

Benign

0.69

T;T

Polyphen

0.014

.;B

Vest4

0.053

MVP

0.52

MPC

0.15

ClinPred

0.0065

GERP RS

0.47

Varity_R

0.041

gMVP

0.38

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