Is MECP2 p.Pro191Ser (c.571C>T) pathogenic?

MECP2 p.Pro191Ser (c.571C>T) is classified Uncertain significance in MECP2 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-10-11). AlphaMissense: likely benign (0.0775); Very rare (popmax 0.000223%, nfe); Associated with severe neonatal-onset encephalopathy with microcephaly.

What condition is associated with MECP2 p.Pro191Ser (c.571C>T)?

MECP2 p.Pro191Ser (c.571C>T) is associated with severe neonatal-onset encephalopathy with microcephaly, Rett syndrome (ClinVar).

How common is MECP2 p.Pro191Ser (c.571C>T) in the general population?

MECP2 p.Pro191Ser (c.571C>T) is very rare (popmax 0.000223%, nfe) (gnomAD).

How is MECP2-related severe neonatal encephalopathy inherited?

Typically X-linked recessive (Orphanet). A genetic counselor can assess individual risk for a family.

What do computational predictors say about MECP2 p.Pro191Ser (c.571C>T)?

AlphaMissense predicts likely benign (score 0.0775) — an in-silico prediction, not a clinical call.

MECP2 p.Pro191Ser

c.571C>T · rs1362774583 · VCV3066399

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.0775 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.000223%, nfe)

Missense predictors

1/2 damaging

AlphaMissense, SaProt · REVEL indeterminate

Conditions

severe neonatal-onset encephalopathy with microcephaly

Computational evidence

Protein change
AlphaMissense	0.0775	likely benign
REVEL	0.432	indeterminate
SaProt	LLR -10.33	damaging
⇒ SaProt calls this damaging; AlphaMissense does not; REVEL is indeterminate.
Splicing
SpliceAI	<0.2	no splice effect predicted · four deltas, not one · how we know
Constraint at this position
Conservation	phyloP 12	GERP 1.3, phastCons 1
Regional constraint	o/e 1.55	unconstrained · MANE · 1,052 bp · p 2.6e-22 · regional, not allelic
Overall
CADD	21.5	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

⚠ Isoform check: AlphaMissense numbered on a different transcript (AM P179S vs ClinVar P191S) — verify the residue.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000223% European (non-Finnish) · 2/895,614 alleles

Filtering AF 3.7e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 1.4e-05%

Overall 0.000165% 2/1,212,219 alleles · very rare exomes 2/1,098,240 · genomes 0/113,979 · joint denominator

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: MECP2
Protein: p.Pro191Ser
Coding: c.571C>T
MANE Select: NM_001110792
dbSNP: rs1362774583
Type: single nucleotide variant
Location: chrX:154031293 (GRCh38)
Structure: AlphaFold pLDDT 57.25 · 11 PDB
Residue 179 UniProt numbering: a β-strand; the 'disordered' region

Full MECP2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

severe neonatal-onset encephalopathy with microcephaly — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: Rett syndrome

For MECP2-related severe neonatal encephalopathy (Orphanet):

Inheritance: X-linked recessive
Onset: Infancy, Neonatal

Similar variants

MECP2 p.Pro191Ala Uncertain significance ★★ ⚠ same residue
MECP2 p.Pro191= Benign ★ same residue
MECP2 p.Pro191Leu Uncertain significance ★ ⚠ same residue
MECP2 c.414-3C>G Pathogenic ★★★ same condition
MECP2 c.62+1G>A Pathogenic ★★★ same condition
MECP2 c.62+2T>G Pathogenic ★★★ same condition
MECP2 p.Ala143Asp Pathogenic ★★★ same condition
MECP2 p.Ala291Val Likely pathogenic ★★★ ⚠ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/mecp2-p-pro191ser (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown