3-14125194-A-G

Position:

• chr3-14125194-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 10P and 4B. PVS1 PM2 BS2

The NM_024334.3(TMEM43):​c.1A>G​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000343 in 1,458,064 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: TMEM43 NM_024334.3 start_lost
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 2.03

Genes affected

TMEM43 (HGNC:28472): (transmembrane protein 43) This gene belongs to the TMEM43 family. Defects in this gene are the cause of familial arrhythmogenic right ventricular dysplasia type 5 (ARVD5), also known as arrhythmogenic right ventricular cardiomyopathy type 5 (ARVC5). Arrhythmogenic right ventricular dysplasia is an inherited disorder, often involving both ventricles, and is characterized by ventricular tachycardia, heart failure, sudden cardiac death, and fibrofatty replacement of cardiomyocytes. This gene contains a response element for PPAR gamma (an adipogenic transcription factor), which may explain the fibrofatty replacement of the myocardium, a characteristic pathological finding in ARVC. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage
• BS2: High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM43	NM_024334.3	c.1A>G	p.Met1?	start_lost	1/12	ENST00000306077.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM43	ENST00000306077.5	c.1A>G	p.Met1?	start_lost	1/12	1	NM_024334.3	P1
TMEM43	ENST00000432444.2	c.1A>G	p.Met1?	start_lost, NMD_transcript_variant	1/13	3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000420 AC: 1 AN: 238152 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 130682

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: 0.00000931

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000343 AC: 5 AN: 1458064 Hom.: 0 Cov.: 32 AF XY: 0.00000276 AC XY: 2 AN XY: 725292

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.00000828 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 5;C3553060:Emery-Dreifuss muscular dystrophy 7, autosomal dominant;C5676964:Auditory neuropathy, autosomal dominant 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Sep 16, 2021

- -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 10, 2016

The p.M1? variant (also known as c.1A>G), located in coding exon 1 of the TMEM43 gene, results from an A to G substitution at nucleotide position 1. This alters the methionine residue at the initiation codon. Based on data from ExAC, the G allele has an overall frequency of <0.01% (1/81382). This amino acid position is highly conserved in available vertebrate species. Variations that modify the initiation codon (ATG) are expected to result in either loss of translation initiation, N-terminal truncation, or cause a shift in the mRNA reading frame. There are alternate in-frame methionines 36 and 41 amino acids downstream from this initiation site which may result in an N-terminal truncation; however, direct evidence is unavailable. While the N-terminus of this protein is expected to be structurally important (Bengtsson L et al. J. Cell. Sci., 2008 Feb;121:536-48), its functional significance is not well established. Furthermore, loss of function of TMEM43 has not been clearly established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. -

Arrhythmogenic right ventricular dysplasia 5 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Aug 15, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.016	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	19
DANN	Benign	0.80
DEOGEN2	Benign	0.0085	T
Eigen	Benign	-0.36
Eigen_PC	Benign	-0.32
FATHMM_MKL	Benign	0.27	N
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.15	D
MetaRNN	Uncertain	0.73	D
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	D
PROVEAN	Benign	-0.65	N
REVEL	Benign	0.28
Sift	Uncertain	0.020	D
Sift4G	Benign	0.41	T
Polyphen		0.32	B
Vest4		0.67
MutPred		0.64		Gain of catalytic residue at M1 (P = 0.0199);
MVP		0.19
ClinPred		0.77	D
GERP RS		3.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.45
gMVP		0.77

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: rs757083718; hg19: chr3-14166694;