1-12011503-G-A

Position:

• chr1-12011503-G-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_014874.4(MFN2):​c.2212G>A​(p.Ala738Thr) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A738V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.56

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 11 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 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 chr1-12011504-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 637283.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• 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). GenCC has associacion of 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, 0.852
• PP5: Variant 1-12011503-G-A is Pathogenic according to our data. Variant chr1-12011503-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 543203.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MFN2	NM_014874.4	c.2212G>A	p.Ala738Thr	missense_variant	19/19	ENST00000235329.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MFN2	ENST00000235329.10	c.2212G>A	p.Ala738Thr	missense_variant	19/19	1	NM_014874.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 25, 2022

This variant has not been reported in the literature in individuals affected with MFN2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 738 of the MFN2 protein (p.Ala738Thr). ClinVar contains an entry for this variant (Variation ID: 543203). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Ala738 amino acid residue in MFN2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21149811, 21601224, 24819634). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.81	D;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D;.
M_CAP	Pathogenic	0.37	D
MetaRNN	Pathogenic	0.85	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Uncertain	-3.3	D;D
REVEL	Pathogenic	0.86
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.049	D;D
Polyphen		1.0	D;D
Vest4		0.52
MutPred		0.83		Loss of catalytic residue at A738 (P = 0.0412);Loss of catalytic residue at A738 (P = 0.0412);
MVP		0.91
MPC		0.78
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.85
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1553146551; hg19: chr1-12071560;