CRANIOCEREBRAL MAGNETIC-RESONANCE-IMAGING MEASUREMENT AND FINDINGS INLESCH-NYHAN-SYNDROME

Objective: To provide the first comprehensive magnetic resonance imagi ng (MRI) assessment of brain in a series of patients with Lesch-Nyhan syndrome (LNS), with emphasis on basal ganglia measurements. Design: R outine readings of MRI studies, repeated reading in random order blind ed to subject diagnosis, and 3-dimensional volumetric measures of basa l ganglia regions. Setting: The Johns Hopkins Hospital, Baltimore, Md. Patients: Seven patients with LNS who have hypoxanthine guanine phosp horibosyltransferase levels less than 1.6% and characteristic clinical features of the disorder, which include hyperuricemia, cognitive impa irment, and dystonic movement disorder, were compared with 7 age-match ed control subjects. Five of the 7 patients demonstrated self-injuriou s behavior. MRI studies were performed using general anesthesia becaus e of the severity of the movement disorder. Main Outcome Measures: Mea surement of brain regions from MRI-obtained images. Results: Routine r eadings described mild cerebral atrophy in 2 of 7 patients, but no cau date or putamen abnormalities were reported. However, on the directed blinded rereading, small caudates were suspected in 5 of 7 cases, and abnormalities in cerebral size and cranium were identified. Volumetric studies of the patients with LNS confirmed a 34% decrease in caudate volume (P<.001), a 17% decrease in total cerebral volume (P<.03), and a 12% decrease in putamen volume (P=.19). Conclusions: To our knowledg e, this is the first demonstration of consistent neuroanatomic abnorma lities in Lh'S. The findings of reduced basal ganglia volume are consi stent with the dystonic movement disorder.