20-17969860-A-G

Variant names:

• chr20-17969860-A-G
• rs778604585
• NM_052865.4:c.1A>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_Supporting PM2

The NM_052865.4(MGME1):​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 0.0000104 in 1,448,992 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: 0.000010 (0 hom.)
• Consequence: MGME1 NM_052865.4 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.707

Genes affected

MGME1 (HGNC:16205): (mitochondrial genome maintenance exonuclease 1) The protein encoded by this gene is a nuclear-encoded mitochondrial protein necessary for the maintenance of mitochondrial genome synthesis. The encoded protein is a RecB-type exonuclease and primarily cleaves single-stranded DNA. Defects in this gene have been associated with mitochondrial DNA depletion syndrome-11. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2015]

OVOL2 (HGNC:15804): (ovo like zinc finger 2) This gene encodes a member of the evolutionarily conserved ovo-like protein family. Mammalian members of this family contain a single zinc finger domain composed of a tetrad of C2H2 zinc fingers with variable N- and C-terminal extensions that contain intrinsically disordered domains. Members of this family are involved in epithelial development and differentiation. Knockout of this gene in mouse results in early embryonic lethality with phenotypes that include neurectoderm expansion, impaired vascularization, and heart anomalies. In humans, allelic variants of this gene have been associated with posterior polymorphous corneal dystrophy. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 3 codons. Genomic position: 17969866. Lost 0.007 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MGME1	NM_052865.4	c.1A>G	p.Met1?	start_lost	Exon 2 of 5	ENST00000377710.10	NP_443097.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MGME1	ENST00000377710.10	c.1A>G	p.Met1?	start_lost	Exon 2 of 5	1	NM_052865.4	ENSP00000366939.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000208 AC: 5 AN: 239940 Hom.: 0 AF XY: 0.0000384 AC XY: 5 AN XY: 130258

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: 0.000174

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000104 AC: 15 AN: 1448992 Hom.: 0 Cov.: 31 AF XY: 0.0000166 AC XY: 12 AN XY: 720752

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: 0.000177

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Aug 04, 2023

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. ClinVar contains an entry for this variant (Variation ID: 1935582). This variant has not been reported in the literature in individuals affected with MGME1-related conditions. This variant is present in population databases (rs778604585, gnomAD 0.02%). This sequence change affects the initiator methionine of the MGME1 mRNA. The next in-frame methionine is located at codon 3. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	0.76
DANN	Benign	0.89
DEOGEN2	Benign	0.0030	T;T;T
Eigen	Benign	-0.94
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.050	N
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Benign	0.0052	T
MetaRNN	Uncertain	0.52	D;D;D
MetaSVM	Benign	-0.99	T
PROVEAN	Benign	-0.51	N;N;N
REVEL	Benign	0.26
Sift	Benign	0.086	T;D;D
Sift4G	Uncertain	0.039	D;D;T
Polyphen		0.0010	B;.;.
Vest4		0.14
MutPred		1.0		Gain of methylation at K2 (P = 0.0449);Gain of methylation at K2 (P = 0.0449);Gain of methylation at K2 (P = 0.0449);
MVP		0.20
ClinPred		0.064	T
GERP RS		0.23
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.21
gMVP		0.11

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: rs778604585; hg19: chr20-17950503;