PITPNM1 and retinal degeneration: Interestingly there was a partial rescue (Fig. 4C–G) of retinal degeneration, ERG amplitude and PIP2 levels on rescuing rdgB9 with RDGBDDHD/4A; analysis of a full deletion of the DDHD domain will be informative in establishing the full impact of loss of function in this domain on the activity of the RDGB protein.