LONG-TERM BENEFIT OF DIETARY TREATMENT IN GYRATE ATROPHY

97th DOG Annual Meeting 1999

K431
LONG-TERM BENEFIT OF DIETARY TREATMENT IN GYRATE ATROPHY

G. Jaissle, M. Seeliger, D. Besch, E. Apfelstedt-Sylla

Background: Gyrate atrophy (GA) is an autosomal-recessive inherited dystrophy of retina and choroid. Typical findings are nightblindness and peripheral visual field defects during the course of the progressive centripetal chorioretinal atrophy, myopia, and a posterior subcapsular cataract (PSC). Metabolic basis is a 10- to 20-fold increase in plasma ornithine (OR) due to a defective ornithine-aminotransferase. Studies on the effect of a diet restricted in the OR precursor arginin have shown a variable outcome. The purpose of this study was to evaluate the effects of an early-onset, long-term diet on the course of the disease.

Methods: A young girl with GA, aged 6 years at the start of treatment, was followed over a period of 12 years while on an arginine-restricted diet. The 8 follow-up examinations during this period included history, basic exami-nation, Goldmann perimetry, dark adaptation threshold, electroretinography (ERG) and blood tests for OR.

Results: On initial presentation, visual acuity was 20/200 OU. The fundus showed the typical circular gyrate chorioretinal atrophy extending from the periphery to the vascular arcades. The visual field was constricted and the ERG was severely reduced. OR was highly increased (773 µMol/l; normal: 24-132 µMol/l), but could be reduced to normal values within a few months by the diet, paralleled by an improvement of the visual acuity to 20/50. Over the years, OR slowly increased to values 2- to 3-fold above of the normal range (compliance ?). During this period, visual acuity and visual fields remained almost constant. About 10 years after the onset of therapy, a noticeable reduction of the visual acuity began, paralleled by the development of a distinct PSC. At the most recent examination, the visual acuity was 20/200, whereas visual field and fundus appearance were unchanged.

Discussion: Most clinical parameters like visual field area and fundus morphology remained constant over a period of 12 years of an early-onset, long-term arginine-restricted diet. The recent reduction in visual acuity during the last two years is most probably caused by PSC formation. Due to this stabilization, we would recommend a dietary treatment in gyrate atrophy patients.

University Eye Hospital, Dept. II, Schleichstr. 12-16, D-72076 Tübingen

Supported by the DFG (SFB 430, project C2) and fortuene grant Nr. 517

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