1-12006679-G-C

Position:

• chr1-12006679-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_014874.4(MFN2):​c.1858G>C​(p.Val620Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000206 in 1,458,936 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. V620I) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.55

Genes affected

MFN2 (HGNC:16877): (mitofusin 2) This gene encodes a mitochondrial membrane protein that participates in mitochondrial fusion and contributes to the maintenance and operation of the mitochondrial network. This protein is involved in the regulation of vascular smooth muscle cell proliferation, and it may play a role in the pathophysiology of obesity. Mutations in this gene cause Charcot-Marie-Tooth disease type 2A2, and hereditary motor and sensory neuropathy VI, which are both disorders of the peripheral nervous system. Defects in this gene have also been associated with early-onset stroke. Two transcript variants encoding the same protein have been identified. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MFN2. . Gene score misZ: 1.6575 (greater than the threshold 3.09). Trascript score misZ: 3.2174 (greater than threshold 3.09). The gene has 123 curated pathogenic missense variants (we use a threshold of 10). The gene has 23 curated benign missense variants. GenCC has associacion of the gene with Charcot-Marie-Tooth disease type 2A2, axonal hereditary motor and sensory neuropathy, hereditary motor and sensory neuropathy type 6, Charcot-Marie-Tooth disease, axonal, autosomal recessive, type 2a2b;, multiple symmetric lipomatosis, severe early-onset axonal neuropathy due to MFN2 deficiency.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.888

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MFN2	NM_014874.4	c.1858G>C	p.Val620Leu	missense_variant	16/19	ENST00000235329.10	NP_055689.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MFN2	ENST00000235329.10	c.1858G>C	p.Val620Leu	missense_variant	16/19	1	NM_014874.4	ENSP00000235329.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251428 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135888

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458936 Hom.: 0 Cov.: 34 AF XY: 0.00000413 AC XY: 3 AN XY: 725828

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: 0.0000166

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 18, 2022

This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 620 of the MFN2 protein (p.Val620Leu). This variant is present in population databases (rs200936779, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with MFN2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.46	T;T
Eigen	Uncertain	0.20
Eigen_PC	Uncertain	0.32
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	D;.
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.89	D;D
MetaSVM	Uncertain	0.63	D
MutationAssessor	Benign	0.83	L;L
PrimateAI	Pathogenic	0.85	D
PROVEAN	Benign	-0.79	N;N
REVEL	Pathogenic	0.65
Sift	Benign	0.21	T;T
Sift4G	Benign	0.30	T;T
Polyphen		0.43	B;B
Vest4		0.79
MutPred		0.79		Loss of MoRF binding (P = 0.0984);Loss of MoRF binding (P = 0.0984);
MVP		0.97
MPC		0.29
ClinPred		0.72	D
GERP RS		4.8
Varity_R		0.20
gMVP		0.61

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: rs200936779; hg19: chr1-12066736;