Teaching Video NeuroImages: Characteristic head jerks in congenital oculomotor apraxia due to Joubert syndrome

Summary

  • 29yo M
  • c/c
    • repetitive head jerks (prev Dx'd as tics)
  • Dx
    • [congenital oculomotor apraxia]
  • Ex
  • Dx
    • [Joubert syndrome]

Further

Terminology

Original

A 29-year-old man presented in our clinic due to repetitive head jerks since his first year of life, which were previously diagnosed as tics. Examination revealed difficulties initiating voluntary saccades in the horizontal plane and disturbed hand–eye coordination with compensatory head thrusts (video and figure, A). The diagnosis of [congenital oculomotor apraxia] was made. Brain MRI revealed cerebellar vermis hypoplasia with elongated superior peduncles (“molar tooth sign”; figure, B) characteristic for [Joubert syndrome], a rare autosomal-recessive ciliopathy with genetic heterogeneity.[1] Joubert syndrome is a common etiology of congenital oculomotor apraxia, a condition first described by Cogan,[2] who considered compensatory head jerks diagnostic.

Figure

Figure

Video-oculographic recording and T1-weighted transversal and sagittal brain MRI
(A) Video-oculographic recording of exemplary saccades to a visual target, jumping rightward from initial fixation to a peripheral position (9/12 degrees of visual angle [dva]) at time “0,” demonstrating prolonged latencies and hypometria of horizontal visually guided saccades. (B) T1-weighted transversal and sagittal brain MRI show hypoplasia of the cerebellar vermis with elongated superior cerebellar peduncles (molar tooth sign) (star) as well as enlargement of the fourth ventricle (arrow).