rs879253925

chr1-11998823-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_014874.4(MFN2):c.653T>C(p.Leu218Pro) 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 7.58

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_014874.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, MFN2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.853
• PP5: Variant 1-11998823-T-C is Pathogenic according to our data. Variant chr1-11998823-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 245744.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MFN2	NM_014874.4	c.653T>C	p.Leu218Pro	missense_variant	7/19	ENST00000235329.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MFN2	ENST00000235329.10	c.653T>C	p.Leu218Pro	missense_variant	7/19	1	NM_014874.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Molecular Diagnostics Laboratory, M Health Fairview: University of Minnesota

Jun 04, 2018

- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 29, 2022

This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 218 of the MFN2 protein (p.Leu218Pro). 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. ClinVar contains an entry for this variant (Variation ID: 245744). This missense change has been observed in individuals with autosomal dominant Charcot-Marie-Tooth disease (PMID: 24444136, 31211173; Invitae). This variant is not present in population databases (gnomAD no frequency). -

Charcot-Marie-Tooth disease Uncertain:1

Uncertain significance, no assertion criteria provided

literature only

Inherited Neuropathy Consortium

-

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 25, 2016

The L218P variant has been previously reported as probably disease causing; however, information about the patient's phenotype and segregation analysis was not provided (Østern et al., 2013). Missense variants in nearby residues (I213T, D214N, F216S, F223L) have been reported in the Human Gene Mutation Database in association with axonal neuropathy or CMT2A (Stenson et al., 2014), supporting the functional importance of this region of the protein. L218P was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The L218P variant is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved across species. However, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic or a rare benign variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D;D
Eigen	Benign	0.13
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;.
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.85	D;D
MetaSVM	Uncertain	0.69	D
MutationAssessor	Uncertain	2.9	M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-6.1	D;D
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		0.082	B;B
Vest4		0.90
MutPred		0.44		Loss of stability (P = 0.0047);Loss of stability (P = 0.0047);
MVP		1.0
MPC		1.2
ClinPred		0.99	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs879253925; hg19: chr1-12058880;