1-11996158-C-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.314C>T(p.Thr105Met) variant causes a missense, splice region 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. 12/21 in silico tools predict a damaging outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. T105R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MFN2 NM_014874.4 missense, splice_region
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 7.57

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 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 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 chr1-11996157-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 543234.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, 0.958
• PP5: Variant 1-11996158-C-T is Pathogenic according to our data. Variant chr1-11996158-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 214652.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-11996158-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MFN2	NM_014874.4	c.314C>T	p.Thr105Met	missense_variant, splice_region_variant	5/19	ENST00000235329.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MFN2	ENST00000235329.10	c.314C>T	p.Thr105Met	missense_variant, splice_region_variant	5/19	1	NM_014874.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 2A2 Pathogenic:4

Pathogenic, criteria provided, single submitter	research	Laboratório de Neurologia Aplicada e Experimental, Faculdade de Medicina de Ribeirao Preto – Universidade de Sao Paulo	Jul 20, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The missense variant p.T105M in MFN2 (NM_014874.4) has been previously reported in affected families (Lawson VH et al,Wang C et al). Functional studies indicate a damaging effect (Amiott EA et al).The p.T105M variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. The p.T105M missense variant is predicted to be damaging by both SIFT and PolyPhen2. The threonine residue at codon 105 of MFN2 is conserved in all mammalian species. The nucleotide c.314 in MFN2 is predicted conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Sep 01, 2022	The variant is not observed in the gnomAD v2.1.1 dataset. Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.94; 3Cnet: 0.98). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000214652). The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 16043786 , 21508331 , 26801520 , 27100445). Different missense changes at the same codon (p.Thr105Ala, p.Thr105Arg, p.Thr105Ser) have been reported to be associated with MFN2 -related disorder (ClinVar ID: VCV000543234 / PMID: 22492563 , 24126688 , 28660751). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jan 01, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Mar 19, 2014	- -

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 31, 2024

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 105 of the MFN2 protein (p.Thr105Met). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Charcot-Marie-Tooth disease (PMID: 15064763, 16043786, 16835246, 21508331, 24957169, 27100445). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 214652). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on MFN2 function (PMID: 17296794, 17959936, 18316077, 19812251). For these reasons, this variant has been classified as Pathogenic. -

Cerebellar ataxia Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Genome Medicine, Institute for Basic Research in Developmental Disabilities

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.57
Cadd	Pathogenic	33
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.88	D;D
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	D;.
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.5	H;H
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-5.5	D;D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.85
MutPred		0.81		Gain of MoRF binding (P = 0.0657);Gain of MoRF binding (P = 0.0657);
MVP		0.99
MPC		1.8
ClinPred		1.0	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.79
gMVP		0.90

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: rs863224069; hg19: chr1-12056215;