Pervasive neuroanatomic abnormalities of the brain in three cases of Rett's syndrome.

Rett's syndrome (RS) is a clinically defined disorder that appears to be unique to girls and is characterized by apparent cognitive and motor skill loss early in life. We report our findings in the brains of three girls with RS, which were studied in comparison with age-matched controls by means of gapless serial section. Reduced neuronal cell size and increased cell-packing density were present throughout the cortical and subcortical regions of the brain in all cases without evidence of active degeneration. These observations appear to be consistent with a curtailment of development. Further, the degree of abnormality in each case correlates more closely with the clinical presentation of the patient at the time of death than with the age of the patient or duration of symptoms.