Figure 4. MERGs from three of the ABCA4 carriers (subject 4, top row; subject 5, second row; and subject 8, third row). The bottom row illustrates a normal mERG in one of the controls. Subject 4 has reduced mERG amplitudes and delayed ITs, although the fundus photos do not show any changes. Subject 5 also has reduced mERG amplitudes and delayed ITs. In this subject, the mERG alterations are accompanied by pigmentary changes in the macula (Figure 1B, C). Subject 8 with quite widely spread retinal flecks (Figure 1J, K) demonstrates delayed mERG ITs but normal mERG amplitudes.