A Girl Without a Chiasm: Electrophysiologic and MRI Evidence for the Absence of Crossing Optic Nerve Fibers in a Girl With a Congenital Nystagmus

Jansonius, Nomdo M.; Vliet, Miranda Van; Cornelissen, Frans W.; Pott, Jan Willem R.; Kooijman, Aart C.

doi:10.1097/00041327-200103000-00007

Cited by 32 publications

(36 citation statements)

References 8 publications

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“…Alternating esotropia and vertical tropias were also documented. A similar case of isolated congenital achiasmia was documented in another 15-year-old girl, but in her case there was only a predominantly horizontal nystagmus, without evidence of a see-saw component (Jansonius et al 2001). See-saw nystagmus was observed in a separate case report involving a 4-month-old female infant with achiasmia, but this patient also had associated brain abnormalities including midline craniofacial cleft lip and nasoethmoidal encephalocele (Leitch et al 1996).…”

Section: Introductionmentioning

confidence: 57%

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant

Pomeranz

Agadzi

Ekesten³

2005

Acta Ophthalmologica Scandinavica

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ABSTRACT. An 18-month-old white boy, observed by his parents at 1-2 months age to have poor visual attentiveness and nystagmus, underwent an ophthalmological evaluation. The patient also underwent unsedated 5-channel flash visual evoked potentials (VEP) and sedated electroretinogram (ERG) testing as well as magnetic resonance imaging (MRI) of the brain and orbits. The VEP in response to monocular stimulation demonstrated occipital asymmetry and was clearly suggestive of crossed asymmetry and also showed right optic nerve hypoplasia. The MRI and fundoscopic examinations supported the findings of achiasmia and probable optic nerve hypoplasia. The patient also had decreased Teller card visual acuity, nystagmus and a variable right esotropia. Neurological examination was normal. The ophthalmological and MRI findings in this 18-month-old male patient support the diagnosis of isolated non-decussating retinal-fugal fibre syndrome as well as hypoplasia of the optic nerve.

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Section: Introductionmentioning

confidence: 57%

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant

Pomeranz

Agadzi

Ekesten³

2005

Acta Ophthalmologica Scandinavica

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“…Apkarian et al (1995) reported on two achiasmatic children suffering from low vision, nystagmus, and advanced concentric visual field defects. A more recent study (Jansonius et al, 2001) reported a further achiasmatic person with marked opthalmological symptoms including nystagmus, reduced visual acuity, and massive visual-field defects. A recent study performed with 12 patients with renal coloboma syndrome detected mutations in the Pax-2 gene and ocular abnormalities within both the retina and the optic nerve (Dureau et al, 2001).…”

Section: Clinical Manifestation Of Pax-2 Defectsmentioning

confidence: 97%

Potential role of Pax‐2 in retinal axon navigation through the chick optic nerve stalk and optic chiasm

et al. 2004

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The degree of fiber decussation at the optic chiasm differs between species, ranging from complete crossing in lower vertebrates to highly complex patterns of intermingling of the fibers from the two eyes seen in mammals and birds. Understanding the genetic control of fiber guidance through the chiasm is therefore important to unravel the developmental mechanisms within the visual system. Here we first report on early stages of chiasm formation, with pioneering axons from the left eye consistently arriving earlier than their counterparts from the right eye. This initial left-right asymmetry is transient and no functional significance is assigned to it yet. Secondly, we examined formation of the chiasm in relation with the expression of the transcription factor Pax-2 along the ventral eye cup and optic nerve stalk. Finally, in order to examine causal involvement of Pax-2 in chiasm formation, the gene was overexpressed along the neuraxis and in the eye cup at embryonic stages preceding the exit of axons from the eye, and hence arrival of axons at the chiasm. When studied with neuroanatomical tracing, Pax-2 overexpression resulted in visibly anomalous decussation of axons at the chiasm. A likely consequence of this perturbation was erroneous arrival of axons at the tectum, as observed by anterograde staining from the retina. These data suggest that balanced expression of Pax-2 results in the correct formation of the chick chiasm at early stages by imposing accurate pathfinding within the optic stalk and the midline.

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“…It is, therefore, not surprising that malformations of the chiasm are also found in human syndromes that affect the visual system. Apkarian et al [3] and Jansonius et al [32] reported on three achiasmatic children suffering from low vision, nystagmus and advanced concentric VFDs. Apkarian et al [2] described misrouting of retinofugal fibres in neonates with albinism.…”

Section: Neuroanatomical Considerationsmentioning

confidence: 99%

Distribution of scotoma pattern related to chiasmal lesions with special reference to anterior junction syndrome

Schiefer

Isbert

Mikolaschek

et al. 2004

Graefe's Arch Clin Exp Ophthalmol

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In patients with chiasmal lesions, incomplete involvement of the temporal hemifields in both eyes was the most frequent event (22%), followed by anterior junction syndrome (13%). The latter entity at least clinically indicates the proximity of the pre-chiasmal ipsilateral optic nerve and decussating fibres emanating from the inferior nasal hemiretina of the fellow eye. However, this cannot provide conclusive evidence for the existence of anterior Wilbrand's knee.

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A Girl Without a Chiasm: Electrophysiologic and MRI Evidence for the Absence of Crossing Optic Nerve Fibers in a Girl With a Congenital Nystagmus

Cited by 32 publications

References 8 publications

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant

Potential role of Pax‐2 in retinal axon navigation through the chick optic nerve stalk and optic chiasm

Distribution of scotoma pattern related to chiasmal lesions with special reference to anterior junction syndrome

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