Rett Syndrome - Variants of Rett Syndrome

Variants of Rett Syndrome

The clinical signs of Rett syndrome typical form are perfectly identified (e.g. see above). In addition to the classical form of Rett syndrome, several «atypical forms» have been described over the years, the main groups are:

• Congenital variant (Rolando variant): in this severe subtype of Rett syndrome, the development of the patients and their head circumference are abnormal from birth. The typical gaze of Rett syndrome patients is usually absent;
• Zappella variant of Rett Syndrome or preserved speech variant: in this subtype of Rett syndrome the patients acquire some manual skills and language is partially recovered around the age of 5 years (that is after the regression phase). Height, weight and head circumference are often in the normal range, and a good gross motor function can be observed. The Zappella variant is a milder form of Rett syndrome;
• Hanefeld variant or early epilepsy variant. In this form of Rett syndrome, the patients suffer from epilepsy before 5 months of age.

The definition itself of the Rett syndrome has been refined over the years: as the atypical forms subsist near to the classical form (Hagberg & Gillberg, 1993), the "Rett Complex" terminology has been introduced.