chr17-78131679-G-A

Position:

• chr17-78131679-G-A

Variant summary

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

The NM_152468.5(TMC8):​c.91G>A​(p.Gly31Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000176 in 1,422,358 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. G31G) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000018 (0 hom.)
• Consequence: TMC8 NM_152468.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.38

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=0.025577843).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMC8	NM_152468.5	c.91G>A	p.Gly31Ser	missense_variant	2/16	ENST00000318430.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMC8	ENST00000318430.10	c.91G>A	p.Gly31Ser	missense_variant	2/16	1	NM_152468.5	P2
TMC6	ENST00000322914.7	c.-75+662C>T		intron_variant		1		P1
TMC8	ENST00000589691.1	c.-372+274G>A		intron_variant		1		A2
TMC8	ENST00000590799.5	n.473G>A		non_coding_transcript_exon_variant	2/4	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000112 AC: 2 AN: 177942 Hom.: 0 AF XY: 0.0000103 AC XY: 1 AN XY: 96850

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: 0.0000275

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000176 AC: 25 AN: 1422358 Hom.: 0 Cov.: 32 AF XY: 0.0000170 AC XY: 12 AN XY: 704084

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: 0.0000219

Gnomad4 OTH exome AF: 0.0000170

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000343 AC: 4

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

Dec 15, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. This variant has not been reported in the literature in individuals affected with TMC8-related conditions. This variant is present in population databases (rs767843139, gnomAD 0.003%). This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 31 of the TMC8 protein (p.Gly31Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.091
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.67
CADD	Benign	0.048
DANN	Benign	0.87
DEOGEN2	Benign	0.0037	.;T
Eigen	Benign	-2.2
Eigen_PC	Benign	-2.2
FATHMM_MKL	Benign	0.016	N
LIST_S2	Benign	0.57	T;T
M_CAP	Benign	0.023	T
MetaRNN	Benign	0.026	T;T
MetaSVM	Benign	-0.91	T
MutationAssessor	Benign	-1.0	.;N
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	0.88	.;N
REVEL	Benign	0.036
Sift	Benign	0.77	.;T
Sift4G	Benign	0.66	T;T
Polyphen		0.0	.;B
Vest4		0.065
MutPred		0.20		Gain of phosphorylation at G31 (P = 0.018);Gain of phosphorylation at G31 (P = 0.018);
MVP		0.33
MPC		1.0
ClinPred		0.050	T
GERP RS		-6.3
Varity_R		0.025
gMVP		0.32

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: rs767843139; hg19: chr17-76127760;