Five new consanguineous families with horizontal gaze palsy and progressive scoliosis and novel ROBO3 mutations
ABSTRACT Horizontal gaze palsy and progressive scoliosis (HGPPS) is an autosomal recessive neurologic disorder caused by homozygous or compound heterozygous mutations in the ROBO3 gene on chromosome 11. We clinically evaluated seven individuals with HGPPS from five previously unreported consanguineous families. We sequenced ROBO3 in all affected individuals, additional unaffected members of each family, and ethnic controls. All affected individuals had severe horizontal gaze restriction, progressive scoliosis, and lower brainstem hypoplasia on neuroimaging, the hallmarks of this syndrome. One individual experienced head trauma with a right subdural hematoma associated with a right hemiparesis, observations that confirm clinically for the first time that corticospinal tracts in HGPPS are uncrossed. We found five novel homozygous ROBO3 mutations (four missense mutations and one base deletion) distributed throughout the extracellular domain of the gene. The ROBO3 gene does not appear to have an obvious hot spot area for mutations; therefore, we recommend sequencing all exons and exon-intron boundaries in patients with clinical and/or radiologic features of HGPPS.
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ABSTRACT: Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disorder caused by mutations in the ROBO3 gene, resulting in a critical absence of crossing fibers in the brainstem. We present a patient with ipsilateral hemiparesis caused by putaminal hemorrhage who had a history of horizontal gaze paralysis and scoliosis since childhood. Diffusion tensor imaging (DTI) tractography confirmed the presence of uncrossed corticospinal tracts. Sequence analysis of the entire ROBO3 coding regions revealed a novel nonsense mutation. We report the first known HGPPS case with intracranial hemorrhage and ROBO3 mutation showing an absence of major crossing pathways by DTI.BMC Neurology 12/2015; 15(1):286. DOI:10.1186/s12883-015-0286-4 · 2.49 Impact Factor
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ABSTRACT: Clinical and molecular characterization of patients with horizontal gaze palsy with progressive scoliosis (HGPPS) to extend existing knowledge of the phenotype caused by mutations in the Roundabout homolog of Drosophila 3 (ROBO3) gene. Four patients (aged 6 months to 13 years), two of them siblings, with features of horizontal gaze palsy and their parents were examined clinically and by molecular testing of the ROBO3 gene. The three families were unrelated, but parents in each family were consanguineous. We identified three novel homozygous ROBO3 mutations in four patients with typical ophthalmologic signs of HGPPS. We found an exonic insertion/deletion mutation (c.913delAinsTGC; p.Ile305CysfsX13), a 31 bp deletion including the donor splice site of exon 17 and adjacent exonic and intronic sequences (c.2769_2779del11, 2779+1_+20del20), and a missense mutation located next to a splice donor site (c.3319A>C) resulting in skipping of exon 22, as shown by cDNA analysis. We describe three novel mutations in the ROBO3 gene and the detailed clinical phenotype of HGPPS. One patient displayed marked convergence upon attempting smooth pursuits to both sides. In one patient, the typical ophthalmologic phenotype, the neuroradiologic findings, and molecular testing led to the diagnosis even before scoliosis developed. In addition to the typical magnetic resonance imaging brain signs of HGPPS, this patient had marked hypoplasia of the frontal lobes and corpus callosum. In summary, diagnosis of HGPPS may be established by ophthalmologic and molecular investigation early in life, allowing ongoing orthopedic surveillance from an early stage.Molecular vision 07/2011; 17:1978-86. · 2.25 Impact Factor
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ABSTRACT: Commissural neurons project their axons across the midline of the nervous system to contact neurons on the opposite side. Although their existence has been known for more than a century, the function of brain commissures, as well as their diversity and evolutionary advantage, are far from understood. Recent genetic studies in mammals have led to the identification of subsets of commissural neurons, which, in the hindbrain and spinal cord, control the tuning and bilateral coordination of locomotion. The molecular mechanisms and transcriptional programs which specify axonal laterality during development are also now being elucidated. Finally, new studies have confirmed that axonal laterality is plastic and that facilitating the commissural sprouting of axon collaterals might influence functional recovery after brain injury.Trends in Neurosciences 09/2014; 37(10). DOI:10.1016/j.tins.2014.08.009 · 12.90 Impact Factor