1-11992662-A-G

Variant names:

• chr1-11992662-A-G
• rs1060501920
• NM_014874.4:c.283A>G

Variant summary

Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PM1 PM2 PM5 PP2 PP5_Very_Strong

The NM_014874.4(MFN2):​c.283A>G​(p.Arg95Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R95S) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.88
• Publications: 4 publications found

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]

MFN2 Gene-Disease associations (from GenCC):

• neuropathy, hereditary motor and sensory, type 6A

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• Charcot-Marie-Tooth disease, axonal, autosomal recessive, type 2a2b;

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• axonal hereditary motor and sensory neuropathy

  Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen
• Charcot-Marie-Tooth disease type 2A2

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• hereditary motor and sensory neuropathy type 6

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• multiple symmetric lipomatosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• severe early-onset axonal neuropathy due to MFN2 deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 15 ACMG points.

• PM1: In a hotspot region, there are 13 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 chr1-11992664-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1455514.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the MFN2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 123 curated pathogenic missense variants (we use a threshold of 10). The gene has 23 curated benign missense variants. Gene score misZ: 1.6575 (below the threshold of 3.09). Trascript score misZ: 3.2174 (above the threshold of 3.09). GenCC associations: The gene is linked to Charcot-Marie-Tooth disease type 2A2, Charcot-Marie-Tooth disease, axonal, autosomal recessive, type 2a2b;, severe early-onset axonal neuropathy due to MFN2 deficiency, hereditary motor and sensory neuropathy type 6, axonal hereditary motor and sensory neuropathy, multiple symmetric lipomatosis, neuropathy, hereditary motor and sensory, type 6A.
• PP5: Variant 1-11992662-A-G is Pathogenic according to our data. Variant chr1-11992662-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 408326.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014874.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFN2	NM_014874.4	MANE Select	c.283A>G	p.Arg95Gly	missense	Exon 4 of 19	NP_055689.1
	MFN2	NM_001127660.2		c.283A>G	p.Arg95Gly	missense	Exon 3 of 18	NP_001121132.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFN2	ENST00000235329.10	TSL:1 MANE Select	c.283A>G	p.Arg95Gly	missense	Exon 4 of 19	ENSP00000235329.5
	MFN2	ENST00000675298.1		c.283A>G	p.Arg95Gly	missense	Exon 4 of 19	ENSP00000501839.1
	MFN2	ENST00000675817.1		c.283A>G	p.Arg95Gly	missense	Exon 4 of 20	ENSP00000502422.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Nov 10, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 95 of the MFN2 protein (p.Arg95Gly). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 408326). This missense change has been observed in individual(s) with autosomal dominant Charcot-Marie-Tooth disease (PMID: 30642740). It has also been observed to segregate with disease in related individuals. This variant disrupts the p.Arg95 amino acid residue in MFN2. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MFN2 protein function.

not provided Pathogenic:1

Jun 02, 2022

Athena Diagnostics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant segregates with Charcot-Marie-Tooth disease in at least one family. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). The variant is located in a region that is considered important for protein function and/or structure.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T
Eigen	Benign	0.060
Eigen_PC	Benign	0.092
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.52	D
MetaRNN	Uncertain	0.64	D
MetaSVM	Uncertain	0.50	D
MutationAssessor	Benign	1.6	L
PhyloP100		1.9
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-2.0	N
REVEL	Pathogenic	0.72
Sift	Benign	0.37	T
Sift4G	Benign	0.17	T
Polyphen		0.90	P
Vest4		0.84
MutPred		0.47		Loss of stability (P = 0.0126)
MVP		0.92
MPC		1.8
ClinPred		0.87	D
GERP RS		4.6
Varity_R		0.43
gMVP		0.94
Mutation Taster		=9/91	disease causing

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

Other links and lift over

dbSNP: rs1060501920; hg19: chr1-12052719;