Laura Mamounas PhD, Program Director at the National Institute of Neurological Disorder and Stroke (NINDS) at the NIH in Bethesda, discusses the challenges of diagnosing Rett syndrome.

Confidently diagnosing Rett syndrome in patients younger than 2 years of age may be challenging since the symptom profile is highly variable. The average age of patients with typical Rett syndrome at the time of diagnosis is 2.5 years; however, as genetic testing becomes more prevalent, earlier diagnostic confirmation may be possible in the future. The average age of diagnosis for patients with atypical Rett syndrome is 3.8 years.

Since the mutations are not inherited, family history does not play a role in diagnosis. Rather, it is based almost solely on presentation and recognition of the symptomatic pattern. The first sign is the loss of previously acquired skills (also referred to as developmental regression), followed by recovery or stabilization for a time: the absence of purposeful hand movements, motor skills, and the ability to communicate. The other regression of clinical earliest signs are loss of acquired speech and motor skills, repetitive hand movements, breathing irregularities, and seizures.

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