Structural abnormalities of the brain other than molar tooth sign in Joubert syndrome-related disorders.

PURPOSE We performed a retrospective study in which we investigated malformations other than brainstem and vermian dysgenesis in Joubert syndrome-related disorders (JSRD). We investigated the frequency and type of structural abnormalities that coexist with the molar tooth sign (MTS) in JSRD. MATERIALS AND METHODS We searched our archive for the years 2002-2008 in order to find patients with the diagnosis of JSRD. Cranial magnetic resonance imaging studies of 20 patients with the diagnosis of JSRD were reviewed by two neuroradiologists. RESULTS In addition to known anomalies including callosal dysgenesis, heterotopia, polymicrogyria, atretic encephalocele, hypomyelination, and nonobstructive dilatation of lateral ventricles; malformations that have not been previously reported were determined, including cerebellar folial disorganization, hippocampal malformation, temporal lob hypoplasia, ambient cistern lipoma, and parenchymal cyst. CONCLUSION Structural abnormalities associated with the MTS are not rare, and the additional imaging findings may help explain the neurological presentation in these patients.