DECREASE IN BENZODIAZEPINE RECEPTOR-BINDING IN THE BRAINS OF ADULT PATIENTS WITH RETT-SYNDROME

To evaluate benzodiazepine (BZD) receptor binding in the brains of pat ients with the Rett syndrome (RS), three Japanese adult females with s tage IV RS were evaluated by single-photon emission computed tomograph y (SPECT) using [I-123] iomazenil. The iomazenil images were obtained 20 min and 3 h post-injection and analyzed for BZD receptor binding. T he binding potential (BP) for the BZD receptor was significantly decre ased in the fronto-temporal cortex of the RS patients (P<0.05). They a lso exhibited a decreased BP ratio (BP of each region/BP of cerebellum ) in the fronto-temporal (P<0.01), occipital and parietal (P<0.05) cor tical gray matter as compared with the ratios observed in five healthy male volunteers. In one RS patient, a marked decrease of iomazenil bi nding was observed in the late SPECT images, while the early SPECT ima ges showed well preserved cerebral perfusion. This difference strongly suggests that changes in the BZD receptor in RS are primary abnormali ty, not secondary to a decrease in cerebral blood flow. (C) 1998 Elsev ier Science B.V.