Corpus Callosum Anomalies in Joubert Syndrome: Low Prevalence and Weak Phenotype–Genotype Correlation

Aims: The molar tooth sign (MTS) is the neuroimaging hallmark of Joubert syndrome (JS). Supratentorial findings including hippocampal malrotation, callosal dysgenesis, migration abnormalities, cephaloceles, and ventriculomegaly are present in approximately 30% of JS patients. Mutations in KIF7, one of the genes associated with JS, and the MTS have been reported in acrocallosal syndrome (ACS). This suggests some overlap between JS and ACS. We aimed to (1) estimate the prevalence of callosal anomalies in JS and (2) evaluate whether KIF7 is a major gene causative of this specific phenotype.