What is a signature feature of Rett syndrome?

Rett syndrome is characterized by a unique developmental regression that notably includes the loss of purposeful hand movements, which is a signature feature of the disorder. Initially, children with Rett syndrome exhibit normal development for the first 6 to 18 months of life. However, after this period, they begin to lose acquired skills, particularly the ability to use their hands effectively for purposeful tasks. This can manifest as hand-wringing movements or repetitive behaviors, which replace meaningful use of the hands.

The loss of purposeful hand movements can severely impact the child's ability to engage with their environment and perform everyday tasks. This distinguishes Rett syndrome from other developmental disorders where motor skills may not be as prominently affected. Other features of Rett syndrome, such as communication difficulties and cognitive impairment, may also be present, but the loss of purposeful hand use is the hallmark sign that typically leads to the diagnosis of the condition.