chr17-78131622-G-A

Position:

• chr17-78131622-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_152468.5(TMC8):​c.34G>A​(p.Ala12Thr) 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 1,398,942 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A12V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: TMC8 NM_152468.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0900

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.07650429).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMC8	NM_152468.5	c.34G>A	p.Ala12Thr	missense_variant	2/16	ENST00000318430.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMC8	ENST00000318430.10	c.34G>A	p.Ala12Thr	missense_variant	2/16	1	NM_152468.5	P2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 7.15e-7 AC: 1 AN: 1398942 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 690392

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: 9.25e-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

Aug 09, 2022

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 threonine 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 not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 12 of the TMC8 protein (p.Ala12Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.086
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.57
CADD	Benign	8.0
DANN	Uncertain	0.98
DEOGEN2	Benign	0.0047	.;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.049	N
LIST_S2	Benign	0.45	T;T
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.077	T;T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	0.85	.;L
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.38	.;N
REVEL	Benign	0.086
Sift	Uncertain	0.021	.;D
Sift4G	Benign	0.087	T;D
Polyphen		0.0	.;B
Vest4		0.057
MutPred		0.14		Gain of phosphorylation at A12 (P = 0.0013);Gain of phosphorylation at A12 (P = 0.0013);
MVP		0.17
MPC		1.0
ClinPred		0.080	T
GERP RS		0.25
Varity_R		0.063
gMVP		0.41

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr17-76127703;