Abstract
Abstract: :
Purpose: To characterize retinal function in patients with Adult Refsum Syndrome (ARS) using electroretinography (ERG), and to evaluate possible effects of treatment. ARS is a very rare autosomal recessive peroxisomal multisystem disorder primarily affecting peripheral nerves, cerebellum and retina. Methods: Ten ARS patients of English (7) and Belgian (3) origin had ISCEV-standard (International Society for Clinical Electrophysiology of Vision) electroretinography after they had been both ophthalmologically and neurologically fully ascertained. The diagnosis was based on high plasma phytanic acid (PhyAc) levels. An evaluation of functional evolution over time was possible in 3 patients who had at least two serial ERGs performed. Results: A variable electrodiagnostic and clinical inter- and intrafamilial expressivity was observed. Anosmia, cerebellar ataxia, neurosensory hearing loss, acromelic membranous and osseous dysplasia, peripheral polyneuropathy, cardiac and pupillary abnormalities and ichthyosis were present in some, but not all patients. All patients had severe bilateral retinal degeneration affecting both rod and cone photoreceptors. In those patients in whom several consecutive ERGs were performed, rapid decline of retinal function to either complete or nearly complete extinction of electroretinographic responses was observed. The only patient in this series in whom this degree of ERG abnormality was not present had been receiving regular plasmapheresis and an additional low PhyAc diet, during which time (5 years) no obvious decline in retinal function was observed. Conclusion: The retinal dystrophy in ARS is severe and affects both rod and cone photoreceptors. Early treatment aimed at reducing the plasma PhyAc levels may be effective in modifying progression of the retinal dystrophy. Further studies are necessary to confirm these findings.
Keywords: 395 electroretinography: clinical • 562 retinal degenerations: hereditary • 517 photoreceptors