NM_001110792.2:c.41_57dupGAGGAGGCGAGGAGGAG

Variant names:

• chrX-154097608-T-TCTCCTCCTCGCCTCCTC
• rs1557150846
• NM_001110792.2:c.41_57dupGAGGAGGCGAGGAGGAG

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1 PP5_Very_Strong

The NM_001110792.2(MECP2):​c.41_57dupGAGGAGGCGAGGAGGAG​(p.Arg20GlufsTer30) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 20)
• Consequence: MECP2 NM_001110792.2 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.73
• Publications: 0 publications found

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]

MECP2 Gene-Disease associations (from GenCC):

• chromosome Xq28 duplication syndrome

  Inheritance: XL Classification: DEFINITIVE Submitted by: G2P
• Rett syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics, ClinGen, G2P
• severe neonatal-onset encephalopathy with microcephaly

  Inheritance: XL Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
• syndromic X-linked intellectual disability Lubs type

  Inheritance: XL Classification: DEFINITIVE Submitted by: G2P
• atypical Rett syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• non-syndromic X-linked intellectual disability

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• X-linked intellectual disability-psychosis-macroorchidism syndrome

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• systemic lupus erythematosus

  Inheritance: Unknown Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 730 pathogenic variants in the truncated region.
• PP5: Variant X-154097608-T-TCTCCTCCTCGCCTCCTC is Pathogenic according to our data. Variant chrX-154097608-T-TCTCCTCCTCGCCTCCTC is described in ClinVar as Pathogenic. ClinVar VariationId is 406153.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.41_57dupGAGGAGGCGAGGAGGAG	p.Arg20GlufsTer30	frameshift_variant	Exon 1 of 3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.-120_-104dupGAGGAGGCGAGGAGGAG		5_prime_UTR_variant	Exon 1 of 4	ENST00000303391.11	NP_004983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MECP2	ENST00000453960.7	c.41_57dupGAGGAGGCGAGGAGGAG	p.Arg20GlufsTer30	frameshift_variant	Exon 1 of 3	1	NM_001110792.2	ENSP00000395535.2
MECP2	ENST00000303391.11	c.-120_-104dupGAGGAGGCGAGGAGGAG		5_prime_UTR_variant	Exon 1 of 4	1	NM_004992.4	ENSP00000301948.6

Frequencies

GnomAD3 genomes Cov.: 20

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 20

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Severe neonatal-onset encephalopathy with microcephaly Pathogenic:1

Aug 21, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in MECP2 are known to be pathogenic (PMID: 12180070). This variant has been reported to be de novo in an individual affected with Rett syndrome (PMID: 27171548). This variant is not present in population databases (ExAC no frequency). This sequence change inserts 17 nucleotides in exon 1 of the MECP2 mRNA (NM_001110792.1:c.41_57dup), causing a frameshift at codon 20. This creates a premature translational stop signal (p.Arg20Glufs*30) and is expected to result in an absent or disrupted protein product. -

not provided Pathogenic:1

Aug 12, 2020

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 27171548) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.7
Mutation Taster		=1/199	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1557150846; hg19: chrX-153363065;