X-154030886-G-C

Variant names:

• chrX-154030886-G-C
• rs61751446
• NM_001110792.2:c.978C>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_001110792.2(MECP2):​c.978C>G​(p.Ile326Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I326I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 23)
• Consequence: MECP2 NM_001110792.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.216
• 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: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 6 uncertain in NM_001110792.2
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.40094292).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MECP2	NM_001110792.2	c.978C>G	p.Ile326Met	missense_variant	Exon 3 of 3	ENST00000453960.7	NP_001104262.1
MECP2	NM_004992.4	c.942C>G	p.Ile314Met	missense_variant	Exon 4 of 4	ENST00000303391.11	NP_004983.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MECP2	ENST00000453960.7	c.978C>G	p.Ile326Met	missense_variant	Exon 3 of 3	1	NM_001110792.2	ENSP00000395535.2
MECP2	ENST00000303391.11	c.942C>G	p.Ile314Met	missense_variant	Exon 4 of 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:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Jan 16, 2018

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.I314M variant (also known as c.942C>G), located in coding exon 3 of the MECP2 gene, results from a C to G substitution at nucleotide position 942. The isoleucine at codon 314 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Uncertain	0.070	D
BayesDel_noAF	Benign	-0.14
CADD	Benign	8.4
DANN	Uncertain	0.99
DEOGEN2	Benign	0.35	T;.
FATHMM_MKL	Benign	0.053	N
LIST_S2	Uncertain	0.92	D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Benign	0.40	T;T
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Benign	1.4	L;.
PhyloP100		-0.22
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.18	N;N
REVEL	Uncertain	0.48
Sift	Uncertain	0.0060	D;D
Sift4G	Benign	0.22	T;T
Vest4		0.20
ClinPred		0.66	D
GERP RS		-2.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.18
gMVP		0.42
Mutation Taster		=87/13	polymorphism

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

Other links and lift over

dbSNP: rs61751446; hg19: chrX-153296337;