NM_002397.5:c.123_124delTG

Variant names:

• chr5-88804731-TCA-T
• rs1554139771
• NM_002397.5:c.123_124delTG

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_002397.5(MEF2C):​c.123_124delTG​(p.Cys41fs) 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 (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MEF2C NM_002397.5 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.91
• Publications: 1 publications found

Genes affected

MEF2C (HGNC:6996): (myocyte enhancer factor 2C) This locus encodes a member of the MADS box transcription enhancer factor 2 (MEF2) family of proteins, which play a role in myogenesis. The encoded protein, MEF2 polypeptide C, has both trans-activating and DNA binding activities. This protein may play a role in maintaining the differentiated state of muscle cells. Mutations and deletions at this locus have been associated with severe cognitive disability, stereotypic movements, epilepsy, and cerebral malformation. Alternatively spliced transcript variants have been described. [provided by RefSeq, Jul 2010]

MEF2C Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• neurodevelopmental disorder with hypotonia, stereotypic hand movements, and impaired language

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Pathogenic. The variant received 12 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 5-88804731-TCA-T is Pathogenic according to our data. Variant chr5-88804731-TCA-T is described in ClinVar as Pathogenic. ClinVar VariationId is 520573.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MEF2C	NM_002397.5	c.123_124delTG	p.Cys41fs	frameshift_variant	Exon 3 of 11	ENST00000504921.7	NP_002388.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MEF2C	ENST00000504921.7	c.123_124delTG	p.Cys41fs	frameshift_variant	Exon 3 of 11	1	NM_002397.5	ENSP00000421925.5

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:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Sep 25, 2014

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.123_124delTG (p.C41*) alteration, located in CDS 2 (c.55_258) of the MEF2C gene, consists of a deletion of 2 nucleotides from position 123 to 124, causing a translational frameshift with a predicted alternate stop codon. Frameshift alterations are typically deleterious in nature (Richards, 2008). The alteration is not observed in healthy cohorts:_x000D_ Based on data from the NHLBI Exome Sequencing Project (ESP), the MEF2C c.123_124delTG alteration was not observed among 6503 individuals tested. Allele frequency data for this nucleotide position are not currently available from the 1000 Genomes Project and the alteration is not currently listed in the Database of Single Nucleotide Polymorphisms (dbSNP). Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.9
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.24		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.24		Position offset: -25

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

Other links and lift over

dbSNP: rs1554139771; hg19: chr5-88100548;