MECP2

Chr XX-linkedXLRXLD

methyl-CpG binding protein 2

Also known as: AUTSX3, MRX16, MRX79, MRXS13, MRXSL, PPMX, RS, RTS

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]

OMIMResearchGenerating clinical summary…
LOFmechanismX-linked/XLR/XLDLOEUF 0.417 OMIM phenotypes
VCEP Guidelines: Rett/Angelman-like DisordersReleased
View SpecificationsClinGen Panel
Clinical SummaryMECP2
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Gene-Disease Validity (ClinGen)
Rett syndrome · XLDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Moderately constrained gene (pLI 0.89) — some intolerance to loss-of-function variants.
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Clinical Trials
12 active or recruiting trials — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint?
0.41LOEUF
pLI 0.894
Z-score 2.89
OE 0.09 (0.030.41)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint?
-1.21Z-score
OE missense 1.23 (1.111.35)
281 obs / 229.3 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios?
LoF OE?0.09 (0.030.41)
00.351.4
Missense OE?1.23 (1.111.35)
00.61.4
Synonymous OE?2.03
01.21.6
LoF obs/exp: 1 / 11.7Missense obs/exp: 281 / 229.3Syn Z: -7.95
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveMECP2-related duplication syndromeOTHERXLR
definitiveMECP2-related Rett syndromeLOFmonoallelic_X_heterozygous
definitiveMECP2-related encephalopathy neonatal severeLOFXLR

This gene — mechanism propensity

DN
0.2299th %ile
GOF
0.2398th %ile
LOF
0.89top 5%

The highest-scoring mechanism for this gene is loss-of-function (haploinsufficiency).

LOFprediction above median · LOEUF 0.41 · ClinGen HI: Sufficient evidence for dosage pathogenicity

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

MECP2 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

Rett Syndrome

A Novel, Regulated Gene Therapy (NGN-401) Study for Females With Rett Syndrome

ACTIVE NOT RECRUITING
NCT05898620Phase PHASE3Neurogene Inc.Started 2023-06-13
NGN-401
Rett Syndrome

Rett REVOLUTION Trial: An Exploratory Evaluation of the Safety and Efficacy of Vorinostat in Rett Syndrome

RECRUITING
NCT07150013Phase PHASE1Unravel Biosciences, Inc.Started 2026-03-15
Vorinostat (SAHA)Placebo
Pitt Hopkins Syndrome

An Exploratory Evaluation of the Safety and Efficacy of Vorinostat in Pitt Hopkins Syndrome

RECRUITING
NCT07150026Phase PHASE1Unravel Biosciences, Inc.Started 2026-03-15
Vorinostat (SAHA)Placebo
CDKL5CDKL5 Deficiency DisorderCDD

International CDKL5 Clinical Research Network

RECRUITING
NCT05558371University of Colorado, DenverStarted 2021-02-15
No intervention.
RETT Syndrome With Proven MECP2 Mutation

GCB-002 in Treatment of Patients With Rett Syndrome

ENROLLING BY INVITATION
NCT06739434Phase NAGenecombio Ltd.Started 2024-11-11
GCB-002
RETT Syndrome With Proven MECP2 MutationRett Syndrome

Efficacy and Safety of NTI164 in Children and Young Adults With Rett Syndrome

NOT YET RECRUITING
NCT07257978Phase PHASE2, PHASE3Fenix Innovation GroupStarted 2026-07-01
NTI164Placebo
Rett Syndrome

Safety and Preliminary Efficacy of TSHA-102 Gene Therapy in Pediatric Females Aged >2 to <4 Years With Rett Syndrome

RECRUITING
NCT07480564Phase PHASE3Taysha Gene Therapies, Inc.Started 2026-05-08
TSHA-102
Rett Syndrome

Single-Dose AAV-MECP2 Safety/Tolerability and Efficacy in Rett Syndrome

ACTIVE NOT RECRUITING
NCT06856759Phase EARLY_PHASE1Guangzhou Women and Children's Medical CenterStarted 2025-01-14
Intrathecal injection of AAV-MECP2 for the treatment of Rett syndrome
RETT Syndrome With Proven MECP2 Mutation

Repurposing Mirtazapine in Rett Syndrome

RECRUITING
NCT07430046Phase PHASE2University of TriesteStarted 2025-07-09
mirtazapine
Rett Syndrome

A Phase 1/2/3 Study of TSHA-102 Gene Therapy in Females With Rett Syndrome (REVEAL Pivotal Study)

ACTIVE NOT RECRUITING
NCT05606614Phase PHASE3Taysha Gene Therapies, Inc.Started 2023-03-06
TSHA-102
Rett SyndromeRett Syndrome, AtypicalGenetic Disease

Rett Syndrome Registry

RECRUITING
NCT05432349International Rett Syndrome FoundationStarted 2022-08-02
Rett Syndrome

Safety and Efficacy of TSHA-102 in Pediatric Females With Rett Syndrome (REVEAL Pediatric Study)

ACTIVE NOT RECRUITING
NCT06152237Phase PHASE1, PHASE2Taysha Gene Therapies, Inc.Started 2023-12-12
TSHA-102