chrX-154031329-G-A

Position:

• chrX-154031329-G-A

Variant summary

Our verdict is Pathogenic. Variant got 9 ACMG points: 9P and 0B. PS2 PM2_Supporting PP1_Strong

This summary comes from the ClinGen Evidence Repository: The p.Arg167Trp variant (NM_004992.3) in MECP2 has been reported as a de novo occurrence (biological parentage confirmed) in at least 2 individuals with MECP2-related disorders through testing completed at GeneDx (PS2_very strong). The variant has been reported to segregate in at least five informative meioses in published literature (Couvert et al., 2001) (PP1_strong). The p.Arg167Trp variant in MECP2 is absent from gnomAD (PM2_supporting). In summary, the p.Arg167Trp variant in MECP2 is classified as pathogenic for Rett syndrome based on the ACMG/AMP criteria (PS2_very strong, PP1_strong, PM2_supporting). LINK:https://erepo.genome.network/evrepo/ui/classification/CA170308/MONDO:0010726/016

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000027 (0 hom. 0 hem.)
• Consequence: MECP2 NM_001110792.2 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:15 U:2
• Conservation: PhyloP100: 7.48

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 9 ACMG points.

• PS2: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP1: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MECP2	NM_001110792.2	c.535C>T	p.Arg179Trp	missense_variant	3/3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.499C>T	p.Arg167Trp	missense_variant	4/4	ENST00000303391.11	NP_004983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MECP2	ENST00000453960.7	c.535C>T	p.Arg179Trp	missense_variant	3/3	1	NM_001110792.2	ENSP00000395535.2
MECP2	ENST00000303391.11	c.499C>T	p.Arg167Trp	missense_variant	4/4	1	NM_004992.4	ENSP00000301948.6

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000273 AC: 3 AN: 1098208 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 363562

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000516

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000238

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:15 Uncertain:2

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:7

Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Sep 15, 2022	This variant has been reported in multiple male individuals with an X-linked intellectual developmental disorder. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). Assessment of experimental evidence regarding the effect of this variant on protein function shows this variant causes a chromatin binding defect, increasing the number of chromocenters and decreasing their size (PMID: 27929079). Further research is needed to determine disease consequence. This variant segregates with disease in multiple families. -
Likely pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Apr 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 30, 2024	Heterozygous carrier females with resting tremors have been reported (PMID: 14598336); Functional studies show the R167W mutant protein is defective, as when expressed in mouse myoblast cells, chromocenter clustering reduced in size and increased in number (PMID: 27929079); Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 30083362, 26490184, 11309367, 26350204, 27323888, 27929079, 30536762, 35032046, 34271245, 31440721, 14598336) -

Rett syndrome Pathogenic:4 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 08, 2013	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Rett and Angelman-like Disorders Variant Curation Expert Panel	Dec 13, 2021	The p.Arg167Trp variant (NM_004992.3) in MECP2 has been reported as a de novo occurrence (biological parentage confirmed) in at least 2 individuals with MECP2-related disorders through testing completed at GeneDx (PS2_very strong). The variant has been reported to segregate in at least five informative meioses in published literature (Couvert et al., 2001) (PP1_strong). The p.Arg167Trp variant in MECP2 is absent from gnomAD (PM2_supporting). In summary, the p.Arg167Trp variant in MECP2 is classified as pathogenic for Rett syndrome based on the ACMG/AMP criteria (PS2_very strong, PP1_strong, PM2_supporting). -
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 pathogenic. At least the following criteria are met: Co-segregation with disease in multiple affected family members (> 5 informative meiosis) (PP1_Strong). PMID: 11309367 Has been observed in at least 5 individuals with phenotypes consistent with MECP2-related disease (PS4).(PMID: 11309367, 30536762, ClinVar Variation ID: 143603) This variant is absent from gnomAD (PM2_Supporting). -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Jul 17, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with MECP2-related disease (OMIM). (I) 0108 - This gene is associated with both recessive and dominant disease. Rett syndrome is inherited in an X-linked dominant pattern, while MECP2-related encephalopathy and intellectual disability demonstrate X-linked recessive inheritance (GeneReviews). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to tryptophan. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported many times as pathogenic, and typically affects hemizygous males where the variant was inherited from an asymptomatic mother (PMID: 26490184, ClinVar). However, rare reports of affected females have been described, who presented with nonprogressive resting tremour, epilepsy or a neuropsychiatric phenotype [DECIPHER, PMID: 11309367, Gonzaga-Jauregui C, et al. (2021)]. (SP) 1203 - This variant has been shown to be de novo in the proband (parental status confirmed, by trio analysis). (SP) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Uncertain significance, criteria provided, single submitter	clinical testing	Génétique des Maladies du Développement, Hospices Civils de Lyon	Nov 27, 2017	- -

X-linked intellectual disability-psychosis-macroorchidism syndrome Pathogenic:1 Uncertain:1

Uncertain significance, no assertion criteria provided	curation	RettBASE	Feb 15, 2011	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins-Biomnis	Nov 23, 2022	- -

Severe neonatal-onset encephalopathy with microcephaly Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 09, 2023

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 167 of the MECP2 protein (p.Arg167Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of MECP2-related conditions (PMID: 11309367, 14598336, 26350204, 26490184, 27929079, 30083362). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 143603). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MECP2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects MECP2 function (PMID: 27929079). For these reasons, this variant has been classified as Pathogenic. -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 26, 2019

The p.R167W pathogenic mutation (also known as c.499C>T), located in coding exon 3 of the MECP2 gene, results from a C to T substitution at nucleotide position 499. The arginine at codon 167 is replaced by tryptophan, an amino acid with dissimilar properties. This mutation segregated with disease in four affected males over two generations within a large family and was absent in a healthy maternally related male (Couvert P et al. Hum. Mol. Genet., 2001 Apr;10:941-6). Affected males in this family were noted to have moderate intellectual disability, microcephaly, seizures, hypoactivity, poor coordination, brisk tendon reflexes, difficulties with written language, verbal stereotypies, and resting tremors, which were also observed in two obligate carrier females (Couvert P et al. Hum. Mol. Genet., 2001 Apr;10:941-6; Gomot M et al. Am. J. Med. Genet. A, 2003 Dec;123A:129-39). In another family, this mutation was detected in 3 affected brothers and their mother, who demonstrated skewed X-inactivation (Bianciardi L et al. J. Hum. Genet., 2016 Feb;61:95-101). C2C12 cells expressing this mutation demonstrated an increased number of chromocenters with decreased size (Sheikh TI et al. Sci Rep, 2016 12;6:38590). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

See cases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Sep 16, 2019

ACMG classification criteria: PS3, PS4, PM2, PP3 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.70
CADD	Pathogenic	27
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.26	T
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.54	T
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.84	D
MutationTaster	Benign	1.0	D;D;D
Sift4G	Pathogenic	0.0	D
Vest4		0.54
MVP		0.93
ClinPred		0.97	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs61748420; hg19: chrX-153296780;