EVOLUTION OF OPHTHALMIC AND ELECTROPHYSIOLOGICAL FINDINGS IN IDENTICAL TWIN SISTERS WITH THE CARBOHYDRATE-DEFICIENT GLYCOPROTEIN SYNDROME TYPE-1 OVER A PERIOD OF 14 YEARS

Aims-To evaluate the evolution of ocular and electroretinographic find ings in identical twin sisters with the carbohydrate deficient glycopr otein (CDG) syndrome over a period of 14 years. Methods-Both girls und erwent a clinical ophthalmic examination with funduscopy and an electr ophysiological assessment with recording of flash electroretinogram (F ERG) at the age of 4 years and 18 years. Results-On ophthalmic examina tion at the age of 4 years an alternating convergent squint and a sacc adic pursuit was diagnosed. In both, vision was 6/9 bilaterally. Fundu s examination showed normal optic discs, narrow blood vessels, and a m ild irregular pigmentation in the periphery. In one girl the FERG show ed a recognisable a, b1, and b2-wave with reduced amplitude to less th an 40% of the normal. In the other girl the reduction in amplitude was still more obvious, but for the white flash a small b1-wave was still present. At the age of 18 vision had remained 6/9 in both eyes. Fundu scopy showed pink optic discs, moderately narrowed blood vessels, and bony spicule pigmentary deposits in the mid periphery. The adapto ERG, performed in identical conditions at 18 years of age, showed a comple tely extinguished trace for both eyes. Conclusions-Despite progressive deterioration of ERG findings good central vision was preserved over 14 years.