Brainstem hypoplasia in familial horizontal gaze palsy and scoliosis

Familial horizontal gaze palsy (HGP) has been reported in association with kyphoscoliosis.1,2⇓ In most cases neuroimaging was not performed or was normal. We present two brothers with HGP and kyphoscoliosis (HGPS), in whom MRI showed brainstem dysplasia. Two brothers of Italian origin were evaluated for FCGP and kyphoscoliosis. A sister and a female cousin reportedly had kyphoscoliosis without gross ocular involvement, but no specialized ophthalmologic or neurologic examination had been performed. Both pairs of the patients’ grandparents were first-degree cousins, and the parents were second-degree cousins. ### Patient 1. The older brother presented at 32 years of age with longstanding diplopia. Best-corrected visual acuity was 0.9 in both eyes. Slight left hypotropia was present. Horizontal eye movements including convergence, vestibulo-ocular reflex (VOR), and optokinetic nystagmus (OKN) were absent. Eye movement recordings showed normal vertical saccades and pursuit. Upbeat nystagmus with increasing amplitude during upgaze was observed. Right facial palsy was present. Neurologic examination including EEG examination was otherwise normal. There was no cognitive abnormality. ### Patient 2. The younger brother also had HGPS and kyphoscoliosis. Best-corrected visual acuity was 0.6 in both eyes. He showed moderate right hypertropia. Horizontal VOR and OKN could not be elicited. Convergence was present. Seesaw nystagmus in downgaze was observed. Eye movement recordings showed intact vertical saccades and pursuit. Neurologic examination was otherwise normal without cognitive abnormality. ### Imaging. Images in the axial and coronal planes were obtained on a 1.5 T superconducting magnet …