FA examination of 64 week-old cbs+/+ mice showed normal fundus (Figure 2A), while FA examination of cbs+/− mice (Figure 2C) revealed a fundus with apparent geographic atrophy reflected by retinal loss with a sever decrease in retinal vasculature coupled with a diffuse hyper fluorescence, a suggestive of RPE atrophy. Here, CBS is linked to atrophic macular degeneration.