rs143417446

Positions:

• chr20-17975704-C-G
• chr20-17975704-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM2 PM5 BP4_Moderate

The NM_052865.4(MGME1):​c.532C>G​(p.Arg178Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,246 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R178W) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MGME1 NM_052865.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.69

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr20-17975704-C-T is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.13710383).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MGME1	NM_052865.4	c.532C>G	p.Arg178Gly	missense_variant	3/5	ENST00000377710.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MGME1	ENST00000377710.10	c.532C>G	p.Arg178Gly	missense_variant	3/5	1	NM_052865.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251354 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135848

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461246 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726842

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0075	T;T
Eigen	Benign	-0.19
Eigen_PC	Benign	-0.059
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.70	T;T
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.14	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.1	M;.
MutationTaster	Benign	1.0	D;N;N
PrimateAI	Benign	0.19	T
PROVEAN	Benign	-1.8	N;N
REVEL	Benign	0.11
Sift	Benign	0.45	T;T
Sift4G	Benign	0.50	T;T
Polyphen		0.0080	B;.
Vest4		0.30
MutPred		0.42		Loss of catalytic residue at R178 (P = 0.0437);.;
MVP		0.42
MPC		0.19
ClinPred		0.43	T
GERP RS		4.5
Varity_R		0.33
gMVP		0.41

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs143417446; hg19: chr20-17956347;