Visual Follow-Up in Peroxisomal-Disorder Patients Treated with Docosahexaenoic Acid Ethyl Ester

Abstract

Purpose. To assess the possible beneficial effects of docosahexaenoic acid (DHA) ethyl ester on visual function in DHA-deficient patients with peroxisome biogenesis disorders (PBDs). Methods. A total of 23 patients were studied, of whom 2 had classic Zellweger syndrome and 1 had a D-bifunctional protein (DBP) deficiency. Most of the PBD patients could be followed up, but for only nine of them was there ophthalmic baseline data to enable a full evaluation of the visual effects of the treatment. A daily dose of 200 mg of DHA ethyl ester was given to all patients. Clinical examination, visual evoked potentials (VEPs), and electroretinogram (ERG) were obtained in all cases. Results. Nystagmus disappeared very quickly in all the patients. The retinal appearance remained stable in all but one. Visual acuity was maintained without deterioration in all the patients. The electrophysiological examination showed a general improvement in retinoneural function, better documented in those patients who had undergone a baseline examination, but also in two children whose ERG continued to improve many years after the treatment was initiated. Conclusions. The visual improvement obtained with DHA therapy emphasizes the deleterious role that a DHA deficiency plays on the retina, especially in PBD patients, with retinas virtually devoid of DHA. These data, together with those reported previously, indicate that the DHA deficiency is an important pathogenic factor in peroxisomal disorders and should always be corrected. Treatment with DHA ethyl ester, given as early as possible, is strongly recommended, before the damage becomes irreversible.