A report describes a case of a 7-month-old girl who presented to the pediatric outpatient clinic with developmental delay and abnormal eye movements. 

Her Abnormal eye movements were observed shortly after birth and involved episodic deviation to lateral extremes of gaze, usually alternating and lasting for a few seconds. These movements were present throughout the day, irrespective of any change in color and activity. The child was unable to fixate and follow objects visually between these movements. Parents also noticed that the child could not keep up with developmental milestones. She had a social smile at three months and head control at five months of age and could not sit even with support.

They denied any history of seizures, abnormal breathing patterns, or feeding or swallowing difficulty. She was born at term to non-consanguineous parents and described no significant perinatal asphyxia. 

Examination revealed the child to be awake and alert, only inconsistently focusing visually. She showed intermittent movements of her eyes to extremes of gaze throughout the examination. She interacted with her parents, displayed a social smile, had no neurocutaneous markers, and had a normal ocular examination. 

The examination also revealed mild facial dysmorphism in the form of forehead prominence, deep-set eyes, bilateral epicanthic folds, and low frontal hairline. She displayed no organomegaly, normal Heart and lungs on auscultation, normal cranial nerves and fundus on Neurological examination, hypotonia with normal tendon reflexes on Motor examination, and normal head circumference for age.

The axial T1-weighted and T2-weighted Magnetic resonance (MR) images revealed abnormally oriented and thickened superior cerebellar peduncles that caused a molar tooth configuration. The more caudal T2- and T1-weighted axial MR images revealed the fourth ventricle shaped like a bat wing. Furthermore, T2-weighted axial MR images showed hypoplasia of the vermis, resulting in a median approach of the two cerebellar hemispheres but without evidence of a posterior fossa cyst. The clinical and magnetic resonance imaging (MRI) findings prompted the diagnosis of JS, and the parents were counseled. Follow-up at nine months of age revealed that she could sit without support and has no truncal ataxia or titubation. Her hypotonia was also diminished.

J Pediatr Neurosci. 2011 Jan;6(1):44-7. doi: 10.4103/1817-1745.84407. PMID: 21977088; PMCID: PMC3173915.