Horizontal Gaze Palsy with Progressive Scoliosis in an Infant Diagnosed Before Developing Scoliosis: MRI and DTI Findings

Introduction

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive disorder characterized by absence of conjugate horizontal eye movements, preservation of vertical gaze and progressive scoliosis developing in childhood and adolescence (Crisfield RJ. J Bone Joint Surg 1974; 56: 484–489). HGPPS has been reported in several dozen families in the literature, but overall prevelance is unknown. The syndrome includes a distinctive brainstem malformation and defective crossing of brainstem neuronal pathways. The gene involved encodes the protein ROBO3, which plays a role in axonal guidance mediating major fibers crossing the midline during embryogenesis of the spinal cord (Jen JC et al. Science 2004; 304: 1509–1513).

Magnetic resonance imaging of the brain in HGPPS showed brainstem hypoplasia with absence of facial colliculi, presence of a deep midline pontine cleft (split pons sign), and butterfly configuration of the medulla. DTI imaging depicted absence of decussating superior cerebellar peduncle and transvers pontocerebellar fibers (Rossi A. Am J Neuroradiol 2004; 25(6): 1046–1048).

Scoliosis is a more striking outward sign than ophthalmologic symptoms in HGPPS. However, while ophthalmologic symptoms usually occur at an early age, scoliosis may not ocur before the age of 2. This may delay the diagnosis in infants.

Here, we report the MRI and DTI findings of a 9-month-old infant with ocular findings but no scoliosis, and mention the importance of neuroimaging in the diagnosis of HGPPS in such patients.

Publication History

Article published online:
20 July 2021