rs879253777

Positions:

• chr1-11999009-G-A
• chr1-11999009-G-T

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_014874.4(MFN2):​c.730G>A​(p.Val244Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V244A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.60

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 Pathogenic. Variant got 19 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_014874.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-11999010-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 860582.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant where missense usually causes diseases, MFN2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.943
• PP5: Variant 1-11999009-G-A is Pathogenic according to our data. Variant chr1-11999009-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 243066.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-11999009-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MFN2	NM_014874.4	c.730G>A	p.Val244Met	missense_variant	8/19	ENST00000235329.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MFN2	ENST00000235329.10	c.730G>A	p.Val244Met	missense_variant	8/19	1	NM_014874.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 2A2 Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Lupski Lab, Baylor-Hopkins CMG, Baylor College of Medicine

Aug 18, 2015

This variant has been previously reported as disease-causing and was found in one patient with demyelinating neuropathy and one patient with axonal neuropathy -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jul 01, 2019

For these reasons, this variant has been classified as Pathogenic. A different missense substitution at this codon (p.Val244Leu) has been determined to be likely pathogenic (PMID: 26378787, 26257172). This suggests that the valine residue is critical for MFN2 protein function and that other missense substitutions at this position may also be pathogenic. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). This variant has been reported in multiple individuals affected with Charcot-Marie-Tooth disease (PMID: 15549395, 20008656). This variant has also been shown to be de novo in affected individuals (PMID: 26257172, Invitae). ClinVar contains an entry for this variant (Variation ID: 243066). This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with methionine at codon 244 of the MFN2 protein (p.Val244Met). The valine residue is highly conserved and there is a small physicochemical difference between valine and methionine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.86	D;D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;.
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.4	M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.79	T
PROVEAN	Uncertain	-2.6	D;D
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.86
MutPred		0.80		Gain of catalytic residue at V244 (P = 0.051);Gain of catalytic residue at V244 (P = 0.051);
MVP		0.97
MPC		1.8
ClinPred		0.99	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.84
gMVP		0.95

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: rs879253777; hg19: chr1-12059066;