17-78131566-AGCCTCTACCCGTGCCCGCCGAGATGCT-A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1

The NM_152468.5(TMC8):​c.-20_7delCTCTACCCGTGCCCGCCGAGATGCTGC​(p.Met1_Leu3del) variant causes a start lost, conservative inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000864 in 1,388,910 control chromosomes in the GnomAD database, with no homozygous occurrence. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0000086 ( 0 hom. )

Consequence

TMC8
NM_152468.5 start_lost, conservative_inframe_deletion

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.14

Publications

0 publications found
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]
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]
TMC6 Gene-Disease associations (from GenCC):
  • epidermodysplasia verruciformis, susceptibility to, 1
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • epidermodysplasia verruciformis
    Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PVS1
Start lost variant, no new inframe start found.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TMC8NM_152468.5 linkc.-20_7delCTCTACCCGTGCCCGCCGAGATGCTGC p.Met1_Leu3del start_lost, conservative_inframe_deletion Exon 2 of 16 ENST00000318430.10 NP_689681.2 Q8IU68-1A0A024R8N8B3KXZ8
TMC8NM_152468.5 linkc.-20_7delCTCTACCCGTGCCCGCCGAGATGCTGC 5_prime_UTR_variant Exon 2 of 16 ENST00000318430.10 NP_689681.2 Q8IU68-1A0A024R8N8B3KXZ8

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TMC8ENST00000318430.10 linkc.-20_7delCTCTACCCGTGCCCGCCGAGATGCTGC p.Met1_Leu3del start_lost, conservative_inframe_deletion Exon 2 of 16 1 NM_152468.5 ENSP00000325561.4 Q8IU68-1
TMC8ENST00000318430.10 linkc.-20_7delCTCTACCCGTGCCCGCCGAGATGCTGC 5_prime_UTR_variant Exon 2 of 16 1 NM_152468.5 ENSP00000325561.4 Q8IU68-1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00000734
AC:
1
AN:
136176
AF XY:
0.0000135
show subpopulations
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000198
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000864
AC:
12
AN:
1388910
Hom.:
0
AF XY:
0.00000584
AC XY:
4
AN XY:
685342
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
31504
American (AMR)
AF:
0.00
AC:
0
AN:
35668
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
35722
South Asian (SAS)
AF:
0.00
AC:
0
AN:
79124
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
41342
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
4164
European-Non Finnish (NFE)
AF:
0.0000111
AC:
12
AN:
1078504
Other (OTH)
AF:
0.00
AC:
0
AN:
57746
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000001), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.383
Heterozygous variant carriers
0
1
2
3
4
5
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
Cov.:
33
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000113

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Epidermodysplasia verruciformis Uncertain:1
May 13, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant has not been reported in the literature in individuals affected with TMC8-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.002%). This sequence change affects the initiator methionine of the TMC8 mRNA. The next in-frame methionine is located at codon 26. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
PhyloP100
1.1
Mutation Taster
=115/85
polymorphism

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs1230051290; hg19: chr17-76127647; API