CFHR4 and age-related macular degeneration: The much rarer ΔCFHR1–CFHR4 deletion (also referred to as CNP148) also confers protection against AMD independent of SNPs in CFH (19); because ΔCFHR1–CFHR4 also removes non-coding flanking regions, its protective effect against AMD could either be due to the reduction of FHR-1 and/or FHR-4A levels, or to the absence of regulatory regions relevant for disease pathogenesis.