Congenital brainstem malformation without associated cerebellar disorder is uncommon. Horizontal gaze palsy with progressive scoliosis is one such rare syndrome with brainstem hypoplasia without any disorder of the cerebellum. It has an autosomal recessive inheritance and is characterised by absent horizontal gaze and severe progressive scoliosis from birth. We describe a 58-year-old man with horizontal gaze palsy and severe thoracolumbar scoliosis with typical MR imaging findings of brainstem hypoplasia, and MR tractography confirmation of complete absence of decussation of the pyramidal tract fibers.