Patients with Rett's syndrome typically show normal development until what age?

Rett's syndrome is a neurodevelopmental disorder that primarily affects females and is characterized by normal early development followed by a period of regression. Typically, affected children show normal growth and development until they reach about 6 to 18 months of age. After this developmental window, they begin to lose acquired skills, such as speech and purposeful hand movements.

This timing is crucial because it differentiates Rett's syndrome from other developmental disorders that may present differently in earlier months or years. Around 6 to 18 months, parents and caregivers often notice a decline in social engagement, communication abilities, and motor skills, which are hallmark symptoms of the syndrome. The identification of this age range is vital for diagnosis and for understanding the progression of the disorder.

Other age ranges provided do not align with the typical presentation of Rett's syndrome. For example, regression does not usually begin as early as 3-6 months, nor does it typically occur so late as 2-4 years, which helps in differentiating Rett's from other developmental conditions. Knowing the typical age of regression allows healthcare providers and families to monitor development and seek intervention strategies effectively.