X-154032268-G-C

Position:

• chrX-154032268-G-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The ENST00000453960.7(MECP2):​c.352C>G​(p.Arg118Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R118L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 25)
• Consequence: MECP2 ENST00000453960.7 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 U:1
• Conservation: PhyloP100: 4.35

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 18 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in ENST00000453960.7
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-154032267-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 143535.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987
• PP5: Variant X-154032268-G-C is Pathogenic according to our data. Variant chrX-154032268-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 143533.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MECP2	NM_001110792.2	c.352C>G	p.Arg118Gly	missense_variant	2/3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.316C>G	p.Arg106Gly	missense_variant	3/4	ENST00000303391.11	NP_004983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MECP2	ENST00000453960.7	c.352C>G	p.Arg118Gly	missense_variant	2/3	1	NM_001110792.2	ENSP00000395535
MECP2	ENST00000303391.11	c.316C>G	p.Arg106Gly	missense_variant	3/4	1	NM_004992.4	ENSP00000301948	P1

Frequencies

GnomAD3 genomes Cov.: 25

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 25

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Rett syndrome Pathogenic:1 Uncertain:1

Likely pathogenic, criteria provided, single submitter	curation	Centre for Population Genomics, CPG	Mar 13, 2024	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 likely pathogenic. At least the following criteria are met: Occurs in the well-characterized Methyl-DNA binding (MDB) functional domain of MECP2 (PM1). Has been observed in at least 3 individuals with phenotypes consistent with MECP2-related disease(PS4_Moderate). (PMID: 16473305, 16183801) Computational prediction analysis tools suggests a deleterious impact (REVEL score>= 0.75) (PP3). This variant is absent from gnomAD (PM2_Supporting). -
Uncertain significance, flagged submission	curation	RettBASE	Jan 21, 2008	- -

MECP2-related disorder Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 25, 2023

The MECP2 c.316C>G variant is predicted to result in the amino acid substitution p.Arg106Gly. This variant has been reported in at least 4 affected individuals with a Rett syndrome phenotype. However, at least one unaffected female was identified to be heterozygous for the variant (Proband ID 2195; http://mecp2.chw.edu.au/mecp2/mecp2_variant_page.php?&id=2194; http://mecp2.chw.edu.au/mecp2/mecp2_variant_page.php?&id=2194; Philippe et al. 2006. PubMed ID: 16473305; Bienvenu et al. 2002. PubMed ID: 12180070). X chromosome inactivation is thought to contribute to phenotypic variability in females (Knudsen et al. 2006. PubMed ID: 16823396; Fang et al. 2022. PubMed ID: 35318820). Furthermore, several other missense variants impacting the same amino acid residue (p.Arg106Trp, p.Arg106Gln, p.Arg106Leu) have been reported in individuals with Rett syndrome phenotypes (http://mecp2.chw.edu.au/mecp2/mecp2_upgrade_proband_list_copy.php). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Take together, this variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.67	D
BayesDel_noAF	Pathogenic	0.73
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;.;T;D;D;T;D
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.1	M;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-6.6	D;D;.;.;.;.;.
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D;D;.;.;.;.;.
Sift4G	Uncertain	0.0070	D;T;D;D;.;D;D
Polyphen		1.0	D;D;.;.;.;.;.
Vest4		0.99
MutPred		0.92		Loss of MoRF binding (P = 0.0263);.;Loss of MoRF binding (P = 0.0263);.;Loss of MoRF binding (P = 0.0263);.;.;
MVP		1.0
ClinPred		1.0	D
GERP RS		2.8
Varity_R		0.99
gMVP		1.0

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: rs28934907; hg19: chrX-153297719;