Joubert syndrome is a malformation syndrome affecting brainstem and cerebellum, resulting in early hypotonia, subsequent truncal ataxia, delayed milestones, and, finally, cognitive impairment of varying degrees. Molar tooth sign is the diagnostic neuroimaging finding on axial cuts through the midbrain/hindbrain region. Some mutations (in particular NPHP1, C5orf42, autosomal recessive SUFU variants) tend to be associated with a mild molar tooth, which may be easily overlooked.
May. 21, 2021