Longitudinal study of the early electroretinographic changes in Alström's syndrome.

We obtained serial electroretinograms in four patients aged between 6 months and 5 years with Alström's syndrome and studied the early stages of the severe retinopathy that is characteristic of that disease. The weak electroretinographic signals found at age 6 months demonstrate a severe early cone dysfunction; one year later the cone activity is undetectable. The rod component of the electroretinogram is initially normal but can rapidly deteriorate to become undetectable as early as 5 years of age. These unusual electroretinographic findings are pathognomonic of Alström's syndrome and different from other cone-rod dystrophies or other syndromes with similar phenotypes such as Bardet-Biedl, Laurence-Moon, and Cohen syndromes.