X-154031137-C-A

Position:

• chrX-154031137-C-A

Variant summary

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

The NM_001110792.2(MECP2):​c.727G>T​(p.Gly243Trp) variant causes a missense 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: MECP2 NM_001110792.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.57

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.727G>T	p.Gly243Trp	missense_variant	3/3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.691G>T	p.Gly231Trp	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.727G>T	p.Gly243Trp	missense_variant	3/3	1	NM_001110792.2	ENSP00000395535
MECP2	ENST00000303391.11	c.691G>T	p.Gly231Trp	missense_variant	4/4	1	NM_004992.4	ENSP00000301948	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 23

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Severe neonatal-onset encephalopathy with microcephaly Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 20, 2020

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with MECP2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with tryptophan at codon 231 of the MECP2 protein (p.Gly231Trp). The glycine residue is highly conserved and there is a large physicochemical difference between glycine and tryptophan. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.42	T;.;T;T
FATHMM_MKL	Benign	0.63	D
LIST_S2	Uncertain	0.95	D;D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Uncertain	0.61	D;D;D;D
MetaSVM	Uncertain	0.64	D
MutationAssessor	Benign	1.5	L;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-1.5	N;N;.;.
REVEL	Uncertain	0.50
Sift	Pathogenic	0.0	D;D;.;.
Sift4G	Uncertain	0.0050	D;D;.;D
Polyphen		0.99	D;D;.;.
Vest4		0.51
MutPred		0.25		Gain of solvent accessibility (P = 0.0062);.;Gain of solvent accessibility (P = 0.0062);.;
MVP		0.97
ClinPred		0.97	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.44
gMVP		0.51

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: rs587783139; hg19: chrX-153296588;