rs149997470

Positions:

chr17-78134490-C-T

Variant summary

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

The NM_152468.5(TMC8):c.913C>T(p.Leu305Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00101 in 1,614,094 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 Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.00058 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0011 ( 1 hom. )

Consequence

TMC8
NM_152468.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -0.0400

Variant links:

Genes affected

TMC8 (HGNC:20474): (transmembrane channel like 8) Epidermodysplasia verruciformis (EV) is an autosomal recessive dermatosis characterized by abnormal susceptibility to human papillomaviruses (HPVs) and a high rate of progression to squamous cell carcinoma on sun-exposed skin. EV is caused by mutations in either of two adjacent genes located on chromosome 17q25.3. Both of these genes encode integral membrane proteins that localize to the endoplasmic reticulum and are predicted to form transmembrane channels. This gene encodes a transmembrane channel-like protein with 8 predicted transmembrane domains and 3 leucine zipper motifs. [provided by RefSeq, Jul 2008]

TMC8 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=0.028656483).

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000578 (88/152324) while in subpopulation NFE AF= 0.00112 (76/68026). AF 95% confidence interval is 0.000915. There are 0 homozygotes in gnomad4. There are 42 alleles in male gnomad4 subpopulation. Median coverage is 33. 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
TMC8	NM_152468.5 linkuse as main transcript	c.913C>T	p.Leu305Phe	missense_variant	8/16	ENST00000318430.10	NP_689681.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TMC8	ENST00000318430.10 linkuse as main transcript	c.913C>T	p.Leu305Phe	missense_variant	8/16	1	NM_152468.5	ENSP00000325561	P2	Q8IU68-1

Frequencies

GnomAD3 genomes

AF:

0.000578

AC:

AN:

152206

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000289

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:

0.00112

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000550

AC:

138

AN:

250778

Hom.:

AF XY:

0.000560

AC XY:

AN XY:

135752

show subpopulations

Gnomad AFR exome

AF:

0.0000620

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000925

Gnomad NFE exome

AF:

0.00116

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.00105

AC:

1536

AN:

1461770

Hom.:

Cov.:

AF XY:

0.00103

AC XY:

750

AN XY:

727178

show subpopulations

Gnomad4 AFR exome

AF:

0.000149

Gnomad4 AMR exome

AF:

0.0000894

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.0000938

Gnomad4 NFE exome

AF:

0.00134

Gnomad4 OTH exome

AF:

0.000464

GnomAD4 genome

AF:

0.000578

AC:

AN:

152324

Hom.:

Cov.:

AF XY:

0.000564

AC XY:

AN XY:

74478

show subpopulations

Gnomad4 AFR

AF:

0.000289

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:

0.00112

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000757

Hom.:

Bravo

AF:

0.000631

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00104

AC:

ESP6500AA

AF:

0.000454

AC:

ESP6500EA

AF:

0.00174

AC:

ExAC

AF:

0.000626

AC:

EpiCase

AF:

0.000981

EpiControl

AF:

0.00107

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 03, 2024

The c.913C>T (p.L305F) alteration is located in exon 8 (coding exon 7) of the TMC8 gene. This alteration results from a C to T substitution at nucleotide position 913, causing the leucine (L) at amino acid position 305 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Epidermodysplasia verruciformis

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 13, 2022

This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 305 of the TMC8 protein (p.Leu305Phe). This variant is present in population databases (rs149997470, 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 TMC8-related conditions. ClinVar contains an entry for this variant (Variation ID: 567371). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The phenylalanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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

0.088

BayesDel_addAF

Benign

-0.44

BayesDel_noAF

Benign

-0.45

CADD

Benign

DANN

Benign

0.97

DEOGEN2

Benign

0.0070

T;.

Eigen

Benign

-0.62

Eigen_PC

Benign

-0.57

FATHMM_MKL

Benign

0.17

LIST_S2

Benign

0.67

T;T

M_CAP

Benign

0.024

MetaRNN

Benign

0.029

T;T

MetaSVM

Benign

-0.98

MutationAssessor

Benign

1.2

L;.

MutationTaster

Benign

0.77

D;D

PrimateAI

Benign

0.38

PROVEAN

Benign

-0.95

N;.

REVEL

Benign

0.049

Sift

Benign

0.11

T;.

Sift4G

Benign

0.12

T;T

Polyphen

0.0020

B;.

Vest4

0.20

MVP

0.33

MPC

0.19

ClinPred

0.017

GERP RS

-0.13

Varity_R

0.065

gMVP

0.37

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