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Torrejón de Velasco, Spain

Gazulla J.,Hospital Universitario Miguel Servet | Vela A.C.,Hospital Universitario Miguel Servet | Marin M.A.,Hospital Universitario Miguel Servet | Pablo L.,Hospital Universitario Miguel Servet | And 5 more authors.
Medical Hypotheses | Year: 2011

The autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is considered a neurodegenerative disease caused by mutations in the SACS gene, located on chromosome 13q12.12. It is a syndrome that comprises skeletal, retinal and neurological manifestations, among which feature spasticity, cerebellar ataxia and peripheral neuropathy.Five patients with a molecular diagnosis of ARSACS underwent clinical, radiological, and ophthalmologic examinations. Every one of the identified causal mutations was novel. Spastic ataxia, peripheral neuropathy, pes cavus, and hammertoes were found in every case. T2 and T2-fluid attenuation inversion recovery-weighted MRI sequences demonstrated cerebellar atrophy and a hypointense linear striation at the pons. Tensor diffusion sequences revealed that the hypointense striation corresponded with hyperplasia of the pontocerebellar fibres, which gave place to abnormally thick middle cerebellar peduncles. Stereophotographs of the optic discs showed an increased number of retinal fibres, and ocular coherence tomography, increased thickness of the retinal nerve fibre layer. The authors suggest that the hyperplasic pontocerebellar fibres compress the pyramidal tracts at the pons since a very early stage of central nervous system development, causing spasticity, and may also cause cerebellar atrophy by means of glutamate-induced excitotoxicity. The abnormal amount of retinal fibres traversing the optic discs could have caused the detected mild peripheral visual field defects.Taken together, these facts point to a developmental cause in ARSACS, as it does not exhibit the tissue atrophy characteristic of degenerative diseases. Clinical deterioration in ARSACS seems to be mediated by phenomena (compression of the pyramidal tracts and cerebellar glutamate-mediated excitotoxicity) derived from the developmental anomalies referred to, while the neuromuscular symptoms are caused by a peripheral neuropathy with pathologic features suggestive of a similar origin. These observations should be taken into account when research about the origin of ARSACS is undertaken. © 2011 Elsevier Ltd.

Pablo L.E.,University of Zaragoza | Pablo L.E.,Aragones Institute of Health science | Garcia-Martin E.,University of Zaragoza | Garcia-Martin E.,Aragones Institute of Health science | And 9 more authors.
Molecular Vision | Year: 2011

Purpose: To present full ophthalmologic examination and retinal nerve fiber layer (RNFL) photographs of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) patients showing significant increases in RNFL thickness compared to healthy subjects, but without myelinated retinal fibers. Methods: The study design was observational case series. Ten eyes of five patients with molecular confirmation of ARSACS underwent a full ophthalmologic examination that included clinical history, visual acuity, biomicroscopy of the anterior segment, gonioscopy, Goldmann applanation tonometry, central corneal ultrasonic pachymetry, ophthalmoscopy of the posterior segment, standard automatic perimetry (Humphrey field), simultaneous stereophotographs of the optic disc after mydriasis, a series of five red-free digital fundus photographs for RNFL evaluation, topographic analysis of the optic disc using the Heidelberg retina tomography, and measurement of peripapillary RNFL thickness with Cirrus optical coherence tomography. Results: All patients showed abnormal visual fields, normal optic discs with a mild to strikingly increased visibility of RNFL in color stereophotographs, normal Heidelberg tomography, and moderate to markedly increased RNFL thickness in Cirrus tomography (average thickness ranging from 119 μm to 220 μm). Conclusions: We found evidence of RNFL hypertrophy in ARSACS patients that may have been interpreted as hypermyelinated retinal fibers in previous reports. A revision of ARSACS diagnostic criteria, particularly with regard to retinal alterations, is necessary. © 2011 Molecular Vision.

Gazulla J.,Hospital Universitario Miguel Servet | Benavente I.,Service of Clinical Neurophysiology | Vela A.C.,Hospital Universitario Miguel Servet | Marin M.A.,Hospital Universitario Miguel Servet | And 8 more authors.
Journal of Neurology | Year: 2012

The aim of the study was to enhance our understanding of the pathogenesis of the ataxia of Charlevoix- Saguenay, based on the findings presented herein. Five patients with a molecular diagnosis of this disease underwent clinical, radiological, ophthalmologic and electrophysiological examinations. Five novel mutations, which included nonsense and missense variants, were identified, with these resulting in milder phenotypes. In addition to the usual manifestations, a straight dorsal spine was found in every case, and imaging techniques showed loss of the dorsal kyphosis. Cranial MRI demonstrated hypointense linear striations at the pons. Tensor diffusion MRI sequences revealed that these striations corresponded with hyperplastic pontocerebellar fibres, and tractographic sequences showed interrupted pyramidal tracts at the pons. Ocular coherence tomography demonstrated abnormal thickness of the nerve fibre layer. Electrophysiological studies showed nerve conduction abnormalities compatible with a dysmyelinating neuropathy, with signs of chronic denervation in distal muscles. The authors suggest that the hyperplastic pontocerebellar fibres compress the pyramidal tracts at the pons, and that the amount of retinal fibres traversing the optic discs is enlarged. These facts point to the contribution of an abnormal developmental mechanism in the ataxia of Charlevoix- Saguenay. Accordingly, spasticity would be mediated by compression of the pyramidal tracts, neuromuscular symptoms by secondary axonal degeneration superimposed on the peripheral myelinopathy, while the cause of the progressive ataxia remains speculative. The distinctive aspect of the dorsal spine could be of help in the clinical diagnosis. © Springer-Verlag 2011.

Gazulla J.,Hospital Universitario Miguel Servet | Benavente I.,Service of Clinical Neurophysiology | Lopez-Fraile I.P.,Hospital Universitario Miguel Servet | Tordesillas C.,Section of Neurology | And 3 more authors.
Journal of the Neurological Sciences | Year: 2010

The objective of this article has been to describe the presence of a sensory neuronopathy in a patient harbouring ataxia with oculomotor apraxia type 2 (AOA2). A 40 year-old woman, born to consanguineous parents, presented with ataxia, decreased vibration sense, areflexia, indifferent plantar responses, preserved muscle volume and strength, and oculomotor apraxia; elevated levels of serum alpha-fetoprotein and creatine-kinase were found. A homozygous missense mutation, causing a substitution of a molecule of arginine for histidine at the helicase domain of the senataxin protein, was found. Two electrophysiological studies were performed, in which decreased amplitudes of the sensory action potentials were followed some years later by an absence of sensory action potentials in the lower limbs, and increased latencies in the somatosensory evoked potentials. Motor nerve conduction velocities were normal, and electromyographic recordings did not show abnormalities. Taken together, these findings are suggestive of a progressive sensory neuronopathy. The patterns of neuromuscular disturbance in AOA2 have not been thoroughly defined; therefore, a sensory neuronopathy should be considered part of the spectrum of neuromuscular manifestations in this disease. Genetic analysis may be of help to diagnose cases with unusual neuromuscular characteristics, like the one presented here. © 2010 Elsevier B.V.

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