Joubert syndrome and related disorders: spectrum of neuroimaging findings in 75 patients

A Poretti; TAGM Huisman; I Scheer; E Boltshauser

doi:10.1055/s-0031-1274082

Neuropediatrics, Table of Contents

Joubert syndrome and related disorders: spectrum of neuroimaging findings in 75 patients

A Poretti ¹^,², TAGM Huisman ¹, I Scheer ³, E Boltshauser ²

¹The Johns Hopkins Medical School, Division of Pediatric Radiology, Baltimore, United States
²University Children's Hospital, Department of Pediatric Neurology, Zurich, Switzerland
³University Children's Hospital, Division of Diagnostic Imaging, Zurich, Switzerland

Abstract

Background and purpose: The key neuroimaging hallmarks of Joubert syndrome and related disorders (JSRD) include vermian hypoplasia and the molar tooth sign (MTS). We aimed to look at the full spectrum of neuroimaging findings in JSRD, pointing out unusual observations in particular.

Patients and methods: We reviewed the neuroimaging findings in 75 patients with JSRD, including 13 siblings from 6 families and 4 patients with Oral-facial-digital syndrome type VI (OFD VI).

Results: All patients had vermian dysplasia as well as distortion and enlargement of the fourth ventricle. However, the degree of vermian hypoplasia and form of the MTS were variable. In most patients the morphology of the cerebellar hemispheres was normal and the posterior fossa enlarged. Brainstem morphology was abnormal in about 30% of the patients. Supratentorial findings included hippocampal malrotation, callosal dysgenesis, migration disorders, cephaloceles, and ventriculomegaly. All patients with OFD VI had severe vermian hypoplasia and an enlarged posterior fossa; two also had hypothalamic hamartomas. No neuroimaging-genotype correlation could be found.

Conclusions: This study demonstrates a wide spectrum of infratentorial and supratentorial neuroimaging findings other than vermian hypoplasia and MTS in JSRD. This supports the heterogeneity of JSRD. Differences between neuroimaging findings in siblings provide evidence about intrafamilial heterogeneity. Neuroimaging findings are of limited value in classifying JSRD-patients and in establishing phenotype-genotype correlations. Patients with OFD VI appear to have a more pronounced neuroimaging pattern including severe vermian hypoplasia, enlarged posterior fossa, and hypothalamic hamartomas.