chr17-78131619-C-G

Position:

• chr17-78131619-C-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_152468.5(TMC8):​c.31C>G​(p.Arg11Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000715 in 1,398,168 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. R11R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 7.2e-7 (0 hom.)
• Consequence: TMC8 NM_152468.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.37

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]

TMC6 (HGNC:18021): (transmembrane channel like 6) 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 10 transmembrane domains and 2 leucine zipper motifs. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.06559044).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMC8	NM_152468.5	c.31C>G	p.Arg11Gly	missense_variant	2/16	ENST00000318430.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMC8	ENST00000318430.10	c.31C>G	p.Arg11Gly	missense_variant	2/16	1	NM_152468.5	P2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.00000678 AC: 1 AN: 147546 Hom.: 0 AF XY: 0.0000126 AC XY: 1 AN XY: 79566

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: 0.0000184

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 7.15e-7 AC: 1 AN: 1398168 Hom.: 0 Cov.: 31 AF XY: 0.00000145 AC XY: 1 AN XY: 689996

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: 9.26e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epidermodysplasia verruciformis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change replaces arginine with glycine at codon 11 of the TMC8 protein (p.Arg11Gly). The arginine residue is weakly conserved and there is a moderate physicochemical difference between arginine and glycine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals affected with TMC8-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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	0.056
BayesDel_addAF	Benign	-0.25	T
BayesDel_noAF	Benign	-0.58
CADD	Benign	13
DANN	Benign	0.78
DEOGEN2	Benign	0.011	.;T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.040	N
LIST_S2	Benign	0.40	T;T
M_CAP	Benign	0.066	D
MetaRNN	Benign	0.066	T;T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	1.3	.;L
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.4	.;N
REVEL	Benign	0.10
Sift	Benign	0.24	.;T
Sift4G	Benign	0.086	T;T
Polyphen		0.016	.;B
Vest4		0.031
MutPred		0.15		Gain of loop (P = 0.0502);Gain of loop (P = 0.0502);
MVP		0.24
MPC		1.3
ClinPred		0.066	T
GERP RS		1.5
Varity_R		0.11
gMVP		0.47

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

Other links and lift over

dbSNP: rs1222145664; hg19: chr17-76127700;