Clinical and electroretinographic comparison between Åland Island eye disease and a newly found related disease with X‐chromosomal inheritance

Abstract Two subjects representing ÅIED (Åland Island Eye Disease) and a family with 5 males affected with an ÅIED related X‐linked hereditary eye disease were studied clinically and electrophysiologically. The clinical picture of ÅIED includes myopia and astigmatism, reduced visual acuity, nystagmus, ocular albinism, hemeralopia and dyschromatopsia (No. 300600, McKusick 1990). The subjects with the related disease showed astigmatism with or without myopia, reduced visual acuity, slight hemeralopia, normal color vision in 3/5 subjects, no ocular albinism and nystagmus only in one case. In both diseases the ERG was abnormal showing defective a‐ and b‐waves, but there were also differences. The most notable was the greater reduction of the b‐wave amplitude in the mixed (rod and cone) responses for the white stimulus in the ERG of the ÅIED related disease. With regard to the pathogenesis we propose that in both diseases rod and cone functions are defective but in an ÅIED related disease a defective cone function inhibits the transmission of the rod signals to the rod bipolars, causing greatly reduced mixed responses. The clinical and ERG findings of this study suggest that the 5 subjects of our family do not represent ÅIED but another X‐linked hereditary eye disease. The investigation to find out the gene locus of this disease is going on.