Bilateral horizontal gaze palsy as an initial presentation of a clinically isolated syndrome: A case report

Multiple sclerosis (MS) is the most common demyelinating disease affecting the central nervous system. It has a wide range of manifestations and commonly affects the visual system. Many patients with MS report decreased vision, diplopia, nystagmus, and abnormal ocular motility. Nevertheless, bilateral horizontal gaze palsies are exceptionally rarely seen. We present the case of a 24-year-old female who came to our pediatric ophthalmology clinic complaining of bilateral horizontal gaze palsy, photophobia, and eye pain for 2 days. Although the patient had a family history of MS, there was no similar or previous complaint, with an unremarkable past medical and surgical history. During the examination, she was found to have a complete bilateral absence of horizontal saccade and pursuit, with slight limitations in vertical ones. There was no nystagmus or skew deviation, and the rest of the cranial nerves (CNs) were intact. Her ocular vital signs were normal, and her corrected visual acuity was 20/20 with full-color vision. The rest of the physical and neurological examinations were unremarkable. After referral to neurology, the magnetic resonance imaging showed multiple hyperintense lesions in deep white matter, pons, and midbrain. The correlation of imaging findings with clinical presentation confirmed the diagnosis of a clinically isolated syndrome. Extra-ocular motility (EOM) significantly improved after pulse steroid therapy and five sessions of plasma exchange, but the patient developed 35 prism diopter of acquired concomitant esotropia. She underwent a right medial rectus botulinum toxin injection which dramatically improved her condition, and became orthotropic during the last 2 months of follow-up after the injection.

A Rare Case Report of Eight Syndrome Secondary to Syringomyelia Associated with Type I Chiari Malformation

Eight syndrome is defined as the combination of a unilateral conjugate gaze palsy and ipsilateral seventh cranial nerve palsy. It may occur as a result of demyelinating, vascular, infectious, or compressive lesions of the brainstem localized to the caudal pontine tegmentum. A 43-year-old woman was admitted to our clinic with complaints of headache, inability to look to the left, and weakness on the left side of her face. The complaints had begun abruptly about a month before her admission. Suboccipital decompression surgery for type I Chiari malformation had been performed 10 years earlier. Neuro-ophthalmological examination revealed left-sided horizontal gaze palsy and anisocoria. Cranial and cervical magnetic resonance images revealed cerebellar tonsillar herniation and syringomyelia, the latter of which was considered to be the cause of eight syndrome. No interventions were performed, and periodic follow-up was advised on neurosurgical consultation. Left gaze palsy and facial palsy recovered almost completely in three months, while the anisocoria persisted. Syringomyelia should be considered among the causes of horizontal gaze palsy plus ipsilateral seventh nerve palsy, termed as eight syndrome. Clinical suspicion and appropriate radiological examination can aid in the diagnosis.

Horizontal gaze palsy with progressive scoliosis - A case report

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare congenital disorder characterized by absence of conjugate horizontal eye movements and accompanied by progressive scoliosis developing in childhood and adolescence. It occurs due to mutation in ROBO 3 gene/chromosome 11q23-q25. We report a case of a 60-year-old lady who presented with complaints of defective vision in both eyes. On examination, she had scoliosis with restricted abduction and adduction in both eyes with intact elevation and depression. Magnetic resonance imaging of the brain and orbit showed brainstem hypoplasia with absence of facial colliculi, presence of a deep midline pontine cleft (split pons sign), and a butterfly configuration of the medulla, which are the radiological findings seen in this disorder.

A novel homozygous frameshift mutation in the DCC gene in a Pakistani family with autosomal recessive horizontal gaze palsy with progressive scoliosis-2 with impaired intellectual development

Horizontal Gaze Palsy with Progressive Scoliosis-2 with Impaired Intellectual Development (HGPPS2) is a rare congenital disorder characterized by absence of conjugate horizontal eye movements, and progressive scoliosis developing in childhood and adolescence. We report three new patients with HGPPS2 in a consanguineous Pakistani family, presenting varying degrees of progressive scoliosis, developmental delays, horizontal gaze palsy, agenesis of corpus callosum, and absence of cerebral commissures. Analysis of genotyping data identified shared loss of heterozygosity (LOH) region on chromosomes 5p15.33-15.31, 6q11.2-12, and 18q21.1-21.3. A hypothesis-free, unbiased exome data analysis detected an insertion of nucleotide A (c.2399dupA) in exon 16 of the DCC gene. The insertion is predicted to cause frameshift p.(Asn800Lysfs*11). Interestingly, DCC gene is present in the LOH region on chromosome 18. Variant (c.2399dupA) in the DCC gene is considered as the most probable candidate variant for HGPPS2 based on the presence of DCC in the LOH region, previously reported role of DCC in HGPPS2, perfect segregation of candidate variant with the disease, prediction of variant pathogenicity, and absence of variant in variation databases. Sanger Sequencing confirmed the presence of the novel homozygous mutation in all three patients; the parents were heterozygous carriers of the mutation, in accordance with an autosomal recessive inheritance pattern. DCC encodes a netrin-1 receptor protein; its role in the development of the CNS has recently been established. Biallelic DCC mutations have previously been shown to cause HGPPS2. A novel homozygous variant in patients of the reported family extend the genotypic and phenotypic spectrum of HGPPS2.

Bosley-Salih-Alorainy syndrome in patients from India

Bi-allelic HOXA1 pathogenic variants clinically manifest as two distinct syndromes, Bosley-Salih-Alorainy syndrome (BSAS) and Athabascan brainstem dysgenesis syndrome, mainly reported in two different populations from Saudi Arabia and southwest North America, respectively. Here we report two siblings of Indian origin with BSAS phenotype caused by a novel homozygous exon 2 HOXA1 pathogenic variants.

Clinical and Genetic Heterogeneity in Six Tunisian Families With Horizontal Gaze Palsy With Progressive Scoliosis: A Retrospective Study of 13 Cases

Background: Horizontal Gaze Palsy with Progressive Scoliosis (HGPPS) is a rare autosomal recessive congenital disorder characterized by the absence of conjugate horizontal eye movements, and progressive debilitating scoliosis during childhood and adolescence. HGPPS is associated with mutations of the ROBO3 gene. In this study, the objective is to identify pathogenic variants in a cohort of Tunisian patients with HGPPS and to further define ROBO3 genotype-phenotype correlations. Methods: Thirteen Tunisian patients from six unrelated consanguineous families all manifesting HGPPS were genetically investigated. We searched for the causative variants for HGPPS using classical Sanger and whole exome sequencing. Results: Four distinct homozygous mutations were identified in ROBO3 gene. Two of these were newly identified homozygous and non-synonymous mutations, causing effectively damage to the protein by in silico analysis. The other two mutations were previously reported in Tunisian patients with HGPPS. Mutations were validated by Sanger sequencing in parents and affected individuals. Conclusion: To the best of our knowledge, this is the largest ever reported cohort on families with HGPPS in whom ROBO3 mutations were identified. These molecular findings have expanded our knowledge of the ROBO3 mutational spectrum. The relevance of our current study is two-fold; first to assist proper management of the scoliosis and second to protect families at risk.

Pontine malformation, undecussated pyramidal tracts, and regional polymicrogyria: a new syndrome

BACKGROUND

Horizontal gaze palsy and progressive scoliosis is caused by mutations in the ROBO3 gene, which plays a role in axonal guidance during brain development. Horizontal gaze palsy and progressive scoliosis is characterized by the congenital absence of conjugate lateral eye movements with preserved vertical gaze and progressive scoliosis as well as dysgenesis of brainstem structures and ipsilateral projection of the pyramidal tract.

PATIENT

A 4-year, 11-month, girl presented with psychomotor retardation and autistic traits. Magnetic resonance imaging revealed hypoplasia and malformation of the ventral portion of the pons and medulla oblongata. Diffusion tensor imaging revealed the absence of decussation of the bilateral pyramidal tracts. These findings were similar to the typical findings for horizontal gaze palsy and progressive scoliosis. However, restriction of horizontal eye movement was minimal, and bilateral polymicrogyria were also noted in the occipitotemporal cortex in the present patient. These findings have not been previously reported in patients with horizontal gaze palsy and progressive scoliosis. No mutations in the ROBO3, SLIT1, SLIT2, NTN1, SEMA3 A, or SEMA3 F genes were identified.

CONCLUSION

This child may have a disorder caused by an unidentified factor, other than a mutation in the genes analyzed, involved in corticogenesis, axonal guidance, and brainstem morphogenesis.

Characterization of ocular motor deficits in congenital facial weakness: Moebius and related syndromes

Congenital facial weakness is present in a heterogeneous group of conditions. Among them is Moebius syndrome, which has been defined as a disorder with congenital, non-progressive facial weakness and limited abduction of one or both eyes. It is typically attributed to agenesis of the abducens and facial cranial nerves. This paper details ocular motor findings of 40 subjects (23 months to 64 years; 24 females, 16 males) with congenital facial weakness: 38 presented at a Moebius Syndrome Conference and two were clinic patients. A new classification scheme of patterns based on ocular motor phenotype is presented. Of 40 subjects, 37 had bilateral and three had unilateral facial weakness. The most common ocular motor pattern (Pattern 1, n=17, 43%) was bilateral horizontal gaze palsy with intact vertical range. Pattern 2 (n=10, 26%) was bilateral horizontal gaze palsy with variable vertical limitations. Pattern 3, which was rare, was isolated abduction deficits (n=2, 5%). Others had full motility range and did not meet minimal criteria for the diagnosis of Moebius syndrome (Pattern 4, n=10, 26%). One subject was too severely affected to characterize. Abnormal vertical smooth pursuit was present in 17 (57%) of 30 subjects: nine with Pattern 1, five with Pattern 2, and three with Pattern 4. Abnormal vertical saccades were present in 10 (34%) of 29 subjects. Vertical saccades appeared slow in nine: six with Pattern 1 and three with Pattern 2. Vertical saccades were absent in one subject with Pattern 2. Abnormal vertical optokinetic nystagmus was present in 19 (68%) of 28 subjects: 10 with Pattern 1, six with Pattern 2, one with Pattern 3, and two with Pattern 4. Reduced convergence was present in 19 (66%) of 29 subjects: nine with Pattern 1, six with Pattern 2, one with Pattern 3, and three with Pattern 4. The most common pattern of ocular motor deficit in Moebius syndrome is bilateral horizontal gaze palsy from pontine abducens nuclear defects, rather than abducens nerve involvement. Defects in the range or dynamic properties of vertical movements in subjects with congenital facial weakness may suggest involvement of ocular motor structures in the midbrain, including oculomotor nerves or nuclei, vertical supranuclear saccadic centres, and convergence neurons. Such deficits were found even in subjects with full vertical motility range. Classification of patterns of ocular motor deficits in congenital facial weakness may assist with further delineation of anatomic localization and identification of genetic deficits underlying these disorders.