[Atypical forms of Rett's syndrome].

INTRODUCTION

Females with Rett syndrome (RS) are actually known to present with a more heterogenous pattern of phenotypes than originally considered.

DEVELOPMENT

This means that a number of clinical variants exist. These clinical variants are those patients who present some symptoms of the RS phenotype, but who show considerable variation in type and age of onset, severity of impairments and profile of clinical course. A correct delineation of atypical or variant RS cases is difficult but important. The following RS phenotype expressions are described: forme 'frustre' variant; early seizure type variant; late childhood regression variant; preserved speech variant; congenital RS.

CONCLUSIONS

A model for inclusion criteria to be used for diagnosing as variants in school age has been suggested. The different RS variants are reviewed briefly.