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Excerpted from the GeneReview: MECP2-Related Disorders
MECP2-related disorders in females include classic Rett syndrome, variant Rett syndrome, and mild learning disabilities. A pathogenic MECP2 variant 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 variants 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.

Genes See tests for all associated and related genes

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

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