Rett Syndrome is a neurodevelopmental condition that impacts all areas of an individual’s life, particularly speech and hand use. It develops in infancy and is found almost exclusively in females. Early developmental milestones appear normal (for example, crawling or responding to social cues from parents) but between 6-18 months the child’s development will either stop or regress to a less developed state (for example, if they were able to pick up a book before, they may not be able to now). Repetitive and constant hand movements are a typical hallmark of this condition. Rett Syndrome is not degenerative, meaning many individuals live long into adulthood.
(Sourced from: https://www.rett.ca/rett-syndromertt/what-is-rett-syndrome/)