Gaze Palsy, Familial Horizontal, with Progressive Scoliosis 1

Clinical Characteristics
Ocular Features: 

Horizontal ophthalmoplegia is the ocular hallmark of this condition.  It is often present at birth with complete lack of horizontal gaze but in other individuals develops sometime in the first decade of life.  Horizontal smooth pursuit, saccades, optokinetic nystagmus, and vestibuloocular responses are lacking.  Vertical pursuit movements are usually intact except for smooth pursuit which is often saccadic.  Pendular nystagmus (usually horizontal) may be present and head shaking accompanies the nystagmus in some patients.  Many patients are orthophoric but some have a mild esotropia and/or vertical deviation.  The degree of convergence is variable.  Amblyopia does not usually occur and vision has been described as normal or near normal in spite of the presence of nystagmus.  Fusion and some degree of stereoacuity are generally present.  Compensatory head motion can effectively mask the horizontal palsy.  The ophthalmoplegia is progressive according to descriptions of some patients.

Some individuals are considered to have Duane retraction syndrome or congenital esotropia before the scoliosis becomes apparent.

Systemic Features: 

Progressive thoracolumbar scoliosis begins early in the first decade of life and may be evident by 2 years of life.  MRI reveals hypoplasia of the pons and cerebellar peduncles and electrophysiology studies provides evidence of abnormal (uncrossed) corticospinal and dorsal column-medial lemniscus pathways.  Cranial nerves VI and III seem to be intact.

Neuroimaging in some patients reveals medullary and pontine atrophy with hypoplasia of facial colliculi.

Genetics

Homozygous mutations in the ROBO3 gene (11q24.2) are responsible for this autosomal recessive disorder.  The ROBO3 protein product is important for normal midline axon crossing in the brainstem. Consanguinity is common among parents.

see Gaze Palsy, Familial Horizontal, with Progressive Scoliosis 2 (617542) for another condition with somewhat similar features.

Treatment
Treatment Options: 

Scoliosis may require surgical stabilization.  Physical therapy can be beneficial.

References
Article Title: 

Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis

Jen JC, Chan WM, Bosley TM, Wan J, Carr JR, R?ob U, Shattuck D, Salamon G, Kudo LC, Ou J, Lin DD, Salih MA, Kansu T, Al Dhalaan H, Al Zayed Z, MacDonald DB, Stigsby B, Plaitakis A, Dretakis EK, Gottlob I, Pieh C, Traboulsi EI, Wang Q, Wang L, Andrews C, Yamada K, Demer JL, Karim S, Alger JR, Geschwind DH, Deller T, Sicotte NL, Nelson SF, Baloh RW, Engle EC. Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis. Science. 2004 Jun 4;304(5676):1509-13.

PubMed ID: 
15105459

References

Rohani M, Almasi M, Soltan Sanjari M. Familial Horizontal Gaze Palsy With Progressive Scoliosis. Pediatr Neurol. 2016 Nov;64:103-104.

PubMedID: 27682326

Khan AO, Abu-Amero K. Infantile esotropia with cross-fixation, inability to abduct, and underlying horizontal gaze palsy with progressive scoliosis. J AAPOS. 2014 Jun 24.  [Epub ahead of print].

PubMedID: 24969490

Bosley TM, Salih MA, Jen JC, Lin DD, Oystreck D, Abu-Amero KK, MacDonald DB, al Zayed Z, al Dhalaan H, Kansu T, Stigsby B, Baloh RW. Neurologic features of horizontal gaze palsy and progressive scoliosis with mutations in ROBO3. Neurology. 2005 Apr 12;64(7):1196-203.

PubMedID: 15824346

Jen JC, Chan WM, Bosley TM, Wan J, Carr JR, R?ob U, Shattuck D, Salamon G, Kudo LC, Ou J, Lin DD, Salih MA, Kansu T, Al Dhalaan H, Al Zayed Z, MacDonald DB, Stigsby B, Plaitakis A, Dretakis EK, Gottlob I, Pieh C, Traboulsi EI, Wang Q, Wang L, Andrews C, Yamada K, Demer JL, Karim S, Alger JR, Geschwind DH, Deller T, Sicotte NL, Nelson SF, Baloh RW, Engle EC. Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis. Science. 2004 Jun 4;304(5676):1509-13.

PubMedID: 15105459