NM_014874.4:c.674_680delTGGTGGC

Variant names:

• chr1-11998841-TGCTGGTG-T
• rs1060501915
• NM_014874.4:c.674_680delTGGTGGC

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_014874.4(MFN2):​c.674_680delTGGTGGC​(p.Leu225ProfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L225L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MFN2 NM_014874.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.56
• Publications: 0 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 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-11998841-TGCTGGTG-T is Pathogenic according to our data. Variant chr1-11998841-TGCTGGTG-T is described in ClinVar as Pathogenic. ClinVar VariationId is 408319.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.674_680delTGGTGGC	p.Leu225ProfsTer7	frameshift	Exon 7 of 19	NP_055689.1
	MFN2	NM_001127660.2		c.674_680delTGGTGGC	p.Leu225ProfsTer7	frameshift	Exon 6 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.674_680delTGGTGGC	p.Leu225ProfsTer7	frameshift	Exon 7 of 19	ENSP00000235329.5
	MFN2	ENST00000675298.1		c.674_680delTGGTGGC	p.Leu225ProfsTer7	frameshift	Exon 7 of 19	ENSP00000501839.1
	MFN2	ENST00000675817.1		c.674_680delTGGTGGC	p.Leu225ProfsTer7	frameshift	Exon 7 of 20	ENSP00000502422.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Sep 29, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Charcot-Marie-Tooth disease type 2 Pathogenic:1

Jun 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 408319). This variant has not been reported in the literature in individuals affected with MFN2-related conditions. This sequence change creates a premature translational stop signal (p.Leu225Profs*7) in the MFN2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MFN2 are known to be pathogenic (PMID: 16714318, 16835246, 21715711, 23781337, 26955893).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.6
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1060501915; hg19: chr1-12058898;