1-11999054-C-T

Variant names:

• chr1-11999054-C-T
• rs587777875
• NM_014874.4:c.775C>T
• MFN2 p.Arg259Cys

Variant summary

Our verdict is Pathogenic. The variant received 23 ACMG points: 23P and 0B. PS3 PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_014874.4(MFN2):​c.775C>T​(p.Arg259Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,886 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 14/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV005399932: Missense variants have been functionally proven to result in a dominant negative and gain of function effect on protein function, and are associated with dominant disease. Protein truncating variants have a loss of function mechanism, and are moreso associated with recessive disease (PMIDs: 12527753, 29898954, 36229071);". Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R259H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MFN2 NM_014874.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10 U:1
• Conservation: PhyloP100: 7.57
• Publications: 16 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
• multiple symmetric lipomatosis with partial lipodystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• 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: Labcorp Genetics (formerly Invitae), Orphanet
• 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 23 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV005399932: Missense variants have been functionally proven to result in a dominant negative and gain of function effect on protein function, and are associated with dominant disease. Protein truncating variants have a loss of function mechanism, and are moreso associated with recessive disease (PMIDs: 12527753, 29898954, 36229071)
• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 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 chr1-11999055-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 577496.
• 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, axonal, autosomal recessive, type 2a2b;, multiple symmetric lipomatosis, Charcot-Marie-Tooth disease type 2A2, axonal hereditary motor and sensory neuropathy, neuropathy, hereditary motor and sensory, type 6A, multiple symmetric lipomatosis with partial lipodystrophy, severe early-onset axonal neuropathy due to MFN2 deficiency, hereditary motor and sensory neuropathy type 6.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.956
• PP5: Variant 1-11999054-C-T is Pathogenic according to our data. Variant chr1-11999054-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 155730.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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFN2	NM_014874.4	MANE Select	c.775C>T	p.Arg259Cys	missense	Exon 8 of 19	NP_055689.1	O95140-1
	MFN2	NM_001127660.2		c.775C>T	p.Arg259Cys	missense	Exon 7 of 18	NP_001121132.1	O95140-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFN2	ENST00000235329.10	TSL:1 MANE Select	c.775C>T	p.Arg259Cys	missense	Exon 8 of 19	ENSP00000235329.5	O95140-1
	MFN2	ENST00000675298.1		c.775C>T	p.Arg259Cys	missense	Exon 8 of 19	ENSP00000501839.1	A0A6Q8PFJ4
	MFN2	ENST00000675817.1		c.775C>T	p.Arg259Cys	missense	Exon 8 of 20	ENSP00000502422.1	A0A6Q8PGV8

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461886 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727246

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112006

Other (OTH) AF: 0.0000331 AC: 2 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.00000534 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	Charcot-Marie-Tooth disease type 2A2 (4)
3	-	-	not provided (3)
1	1	-	Charcot-Marie-Tooth disease (2)
1	-	-	Charcot-Marie-Tooth disease type 2 (1)
1	-	-	Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		7.6
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-7.1	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.87
gMVP		0.98
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs587777875;

hg19: chr1-12059111;

COSMIC: COSV52426484;