NM_001110792.2:c.746dupG

Variant names:

• chrX-154031117-A-AC
• rs61749743
• NM_001110792.2:c.746dupG

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_001110792.2(MECP2):​c.746dupG​(p.Gly250TrpfsTer21) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: MECP2 NM_001110792.2 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 1.52

Genes affected

MECP2 (HGNC:6990): (methyl-CpG binding protein 2) DNA methylation is the major modification of eukaryotic genomes and plays an essential role in mammalian development. Human proteins MECP2, MBD1, MBD2, MBD3, and MBD4 comprise a family of nuclear proteins related by the presence in each of a methyl-CpG binding domain (MBD). Each of these proteins, with the exception of MBD3, is capable of binding specifically to methylated DNA. MECP2, MBD1 and MBD2 can also repress transcription from methylated gene promoters. In contrast to other MBD family members, MECP2 is X-linked and subject to X inactivation. MECP2 is dispensible in stem cells, but is essential for embryonic development. MECP2 gene mutations are the cause of most cases of Rett syndrome, a progressive neurologic developmental disorder and one of the most common causes of cognitive disability in females. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Oct 2015]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.502 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-154031117-A-AC is Pathogenic according to our data. Variant chrX-154031117-A-AC is described in ClinVar as [Likely_pathogenic]. Clinvar id is 143666.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MECP2	NM_001110792.2	c.746dupG	p.Gly250TrpfsTer21	frameshift_variant	Exon 3 of 3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.710dupG	p.Gly238TrpfsTer21	frameshift_variant	Exon 4 of 4	ENST00000303391.11	NP_004983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MECP2	ENST00000453960.7	c.746dupG	p.Gly250TrpfsTer21	frameshift_variant	Exon 3 of 3	1	NM_001110792.2	ENSP00000395535.2
MECP2	ENST00000303391.11	c.710dupG	p.Gly238TrpfsTer21	frameshift_variant	Exon 4 of 4	1	NM_004992.4	ENSP00000301948.6

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Rett syndrome Pathogenic:4

-

Molecular Genetics Laboratory, Children's Mercy Hospital and Clinics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 13, 2024

Centre for Population Genomics, CPG

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

This variant has been collected from RettBASE and curated to current modified ACMG/AMP criteria. Based on the classification scheme defined by the ClinGen Rett/Angelman-like Expert Panel for Rett/AS-like Disorders Specifications to the ACMG/AMP Variant Interpretation Guidelines VCEP 3.0, this variant is classified as pathogenic. At least the following criteria are met: Predicted to result in loss of function, and LOF is a known mechanism of disease (PVS1). This variant is absent from gnomAD (PM2_Supporting). Has been observed in at least 2 individuals with phenotypes consistent with MECP2-related disease (PS4_Supporting). (PMID 11462237‚Äö 17986102‚ÄöClinVar Variation ID: 143666) -

Jun 12, 2013

RettBASE

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Jul 14, 2015

Molecular Diagnostics Lab, Nemours Children's Health, Delaware

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Psychomotor arrest; Microcephaly; Partial epilepsy; Spasticity; Scoliosis; Hypercholesterolemia; Characteristic hand movements -

Severe neonatal-onset encephalopathy with microcephaly Pathogenic:1

Sep 16, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gly238Trpfs*21) in the MECP2 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 249 amino acid(s) of the MECP2 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with Rett syndrome (PMID: 11462237, 17986102). ClinVar contains an entry for this variant (Variation ID: 143666). This variant disrupts a region of the MECP2 protein in which other variant(s) (p.Glu455Aspfsx*32, p.Asn470*) have been determined to be pathogenic (PMID: 10814718, 23696494). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Jun 13, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 23262346, 11462237, 30405208, 21831886, 17986102, 11402105, 28947817) -

Autism, susceptibility to, X-linked 3 Pathogenic:1

-

Lifecell International Pvt. Ltd

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A Heterozygous Frameshift variant c.710dupG in Exon 4 of the MECP2 gene that results in the amino acid substitution p.Gly238fs*21 was identified. The observed variant is novel in gnomAD exomes and genomes, respectively. The severity of the impact of this variant on the protein is high, based on the effect of the protein and REVEL score . Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. ClinVar has also classified this variant as Pathogenic (Variant ID: 143666). The observed variant has previously been reported in the patient affected with Rett syndrome (Hoffbuhr K et al 2001). Based on the above evidence this variant has been classified as Likely Pathogenic according to the ACMG guidelines. -

Computational scores

Source: dbNSFP v4.3

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: rs61749743; hg19: chrX-153296568;