case_images: PMC5570108_01
case_images: Older (A) and younger (B) brother showing tonic upgaze and their corresponding sagittal T1 magnetic resonance (MR) image showing cerebellar atrophy (C and D).
case_images: 10.1177_2329048X17726168-fig1.jpg
case_images: PMC5570108_01_10.1177_2329048X17726168-fig1.jpg
case_images: fig1-2329048X17726168
case_images: Neurological examination revealed frequent intermittent tonic upward gaze (Figure 1), vertical and horizontal nystagmus on eye movements, oculomotor apraxia (saccadic initiation failure and impaired voluntary pursuit), severe central hypotonia, hyperreflexia, and limb and truncal ataxia. Magnetic resonance imaging of the brain revealed cerebellar atrophy (Figure 1).