GTR Home > Conditions/Phenotypes > Encephalopathy, neonatal severe, due to MECP2 mutations

Disease characteristics

Excerpted from the GeneReview: MECP2-Related Disorders
MECP2-related disorders in females include classic Rett syndrome, variant Rett syndrome, and mild learning disabilities. A MECP2 mutation in a male is presumed to most often be lethal; phenotypes in rare surviving males are primarily severe neonatal encephalopathy and manic-depressive psychosis, pyramidal signs, Parkinsonian, and macro-orchidism (PPM-X syndrome). Classic Rett syndrome, a progressive neurodevelopmental disorder primarily affecting girls, is characterized by apparently normal psychomotor development during the first six to 18 months of life, followed by a short period of developmental stagnation, then rapid regression in language and motor skills, followed by long-term stability. During the phase of rapid regression, repetitive, stereotypic hand movements replace purposeful hand use. Additional findings include fits of screaming and inconsolable crying, autistic features, panic-like attacks, bruxism, episodic apnea and/or hyperpnea, gait ataxia and apraxia, tremors, seizures, and acquired microcephaly. Atypical Rett syndrome is observed increasingly as MECP2 mutations are identified in individuals previously diagnosed with: clinically suspected but molecularly unconfirmed Angelman syndrome; intellectual disability with spasticity or tremor; mild learning disability; or (rarely) autism. Severe neonatal encephalopathy resulting in death before age two years is the most common phenotype observed in affected males.

Associated genes

  • Also known as: AUTSX3, MRX16, MRX79, MRXS13, MRXSL, PPMX, RS, RTS, RTT, MECP2
    Summary: methyl CpG binding protein 2

Clinical features

Help
  • Apnea
  • Intellectual disability, severe
  • EEG abnormalities
  • Hyperreflexia
  • Respiratory insufficiency
  • Intellectual disability, progressive
  • Seizure
  • Encephalopathy
  • Failure to thrive
  • Feeding difficulties in infancy
  • Progressive microcephaly
  • Global developmental delay
  • Myoclonus
  • Gastroesophageal reflux
  • Rigidity
  • Polymicrogyria
  • Central hypoventilation
  • Muscular hypotonia of the trunk
Show all (18)

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Write to the Help Desk