Visual system involvement in patients with Friedreich's ataxia

Filippo Fortuna, Piero Barboni, Rocco Liguori, Maria Lucia Valentino, Giacomo Savini, Cinzia Gellera, Caterina Mariotti, Giovanni Rizzo, Caterina Tonon, David Manners, Raffaele Lodi, Alfredo A. Sadun, Valerio Carelli

Research output: Contribution to journalArticle

Abstract

Optic neuropathy is common in mitochondrial disorders, but poorly characterized in Friedreich's ataxia (FRDA), a recessive condition caused by lack of the mitochondrial protein frataxin. We investigated 26 molecularly confirmed FRDA patients by studying both anterior and posterior sections of the visual pathway using a new, integrated approach. This included visual field testing and optical coherence tomography (OCT), pattern visual evoked potentials (P-VEPs) and diffusion-weighted imaging. The latter was used to study optic radiation by calculating water apparent diffusion coefficients (ADC). All patients suffered optic nerve involvement with their disorder. Different patterns of visual field defects were observed and a variably reduced retinal nerve fiber layer thickness was seen by OCT in all cases. P-VEPs were abnormal in approximately half of the patients. Decreased visual acuity and temporal optic disc pallor were present in advanced stages of the disease, but only five patients were symptomatic. Two of these patients suffered a sudden loss of central vision, mimicking Leber's hereditary optic neuropathy (LHON), and of the other three symptomatic patients two were noted to be compound heterozygotes. ADC values of optic radiations in patients were significantly higher than controls (P <0.01). Retinal nerve fiber layer thickness at OCT and P-VEPs correlated with age at onset and ICARS total score. ADC values correlated with age at onset, disease duration, GAA triplet expansion size, ICARS total score and P-VEPs. Visual pathway involvement is found consistently in FRDA, being previously underestimated, and we here document that it also involves the optic radiations. Occasional LHON-like cases may occur. However, optic neuropathy in FRDA substantially differs from classic mitochondrial optic neuropathies implying a different pathophysiology of visual system degeneration in this mitochondrial disease.

Original languageEnglish
Pages (from-to)116-123
Number of pages8
JournalBrain
Volume132
Issue number1
DOIs
Publication statusPublished - Jan 2009

Fingerprint

Friedreich Ataxia
Visual Evoked Potentials
Optic Nerve Diseases
Optical Coherence Tomography
Leber's Hereditary Optic Atrophy
Mitochondrial Diseases
Visual Pathways
Radiation
Visual Fields
Nerve Fibers
Age of Onset
Pallor
Mitochondrial Proteins
Optic Disk
Heterozygote
Optic Nerve
Visual Acuity
Water

Keywords

  • Frataxin
  • Friedreich's ataxia
  • Mitochondria
  • OCT
  • Optic neuropathy

ASJC Scopus subject areas

  • Clinical Neurology

Cite this

Visual system involvement in patients with Friedreich's ataxia. / Fortuna, Filippo; Barboni, Piero; Liguori, Rocco; Valentino, Maria Lucia; Savini, Giacomo; Gellera, Cinzia; Mariotti, Caterina; Rizzo, Giovanni; Tonon, Caterina; Manners, David; Lodi, Raffaele; Sadun, Alfredo A.; Carelli, Valerio.

In: Brain, Vol. 132, No. 1, 01.2009, p. 116-123.

Research output: Contribution to journalArticle

Fortuna, Filippo ; Barboni, Piero ; Liguori, Rocco ; Valentino, Maria Lucia ; Savini, Giacomo ; Gellera, Cinzia ; Mariotti, Caterina ; Rizzo, Giovanni ; Tonon, Caterina ; Manners, David ; Lodi, Raffaele ; Sadun, Alfredo A. ; Carelli, Valerio. / Visual system involvement in patients with Friedreich's ataxia. In: Brain. 2009 ; Vol. 132, No. 1. pp. 116-123.
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