rs267608549

Positions:

• chrX-154030920-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001110792.2(MECP2):​c.944T>G​(p.Ile315Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: MECP2 NM_001110792.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 6.68

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MECP2	NM_001110792.2	c.944T>G	p.Ile315Ser	missense_variant	3/3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.908T>G	p.Ile303Ser	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.944T>G	p.Ile315Ser	missense_variant	3/3	1	NM_001110792.2	ENSP00000395535.2
MECP2	ENST00000303391.11	c.908T>G	p.Ile303Ser	missense_variant	4/4	1	NM_004992.4	ENSP00000301948.6

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Rett syndrome Uncertain:2

Uncertain significance, no assertion criteria provided	curation	RettBASE	Jan 21, 2008	- -
Uncertain significance, criteria provided, single submitter	curation	Centre for Population Genomics, CPG	Mar 25, 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 a variant of uncertain significance. At least the following criteria are met: Occurs in the well-characterized Transcriptional repression domain (TRD) of MECP2 (PM1). Computational prediction analysis tools suggests a deleterious impact (REVEL score>= 0.75) (PP3). This variant is absent from gnomAD (PM2_Supporting). -

Severe neonatal-onset encephalopathy with microcephaly Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 29, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MECP2 protein function. ClinVar contains an entry for this variant (Variation ID: 143741). This missense change has been observed in individual(s) with clinical features of Rett syndrome (PMID: 16473305; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 303 of the MECP2 protein (p.Ile303Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.62
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.064	T
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.19	T
M_CAP	Pathogenic	0.94	D
MetaRNN	Uncertain	0.73	D
Sift4G	Benign	0.24	T
Vest4		0.51
MVP		0.98
ClinPred		0.97	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs267608549; hg19: chrX-153296371;