Editing Rett syndrome (section)

===Stage II===
Stage II, or the rapid destructive stage, usually begins between ages 1 and 4 and may last for weeks or months.<ref name=NIH2017/> Its onset may be rapid or gradual as the child loses purposeful hand skills and spoken language.<ref name=NIH2017/> Characteristic hand movements such as wringing, washing, clapping, or tapping, as well as repeatedly moving the hands to the mouth often begin during this stage which is called mouthing.<ref name=NIH2017/> The child may hold the hands clasped behind the back or held at the sides, with random touching, grasping, and releasing.<ref name=NIH2017/> The movements continue while the child is awake but disappear during sleep.<ref name=NIH2017/> Breathing irregularities such as episodes of apnea and hyperventilation may occur, although breathing usually improves during sleep.<ref name=NIH2017/> Some girls also display autistic-like symptoms such as loss of social interaction and communication.<ref name=NIH2017/> Walking may be unsteady and initiating motor movements can be difficult. Slowed head growth is usually noticed during this stage.<ref name=NIH2017/>