Screening of DNA-variants in the properdin gene (CFP) in age-related macular degeneration (AMD).

Several variants in the complement cascade genes (complement factor H [CFH], C2, C3, CFB, and Serping1) have been reported to associate with age-related macular degeneration (AMD). Of these, a member of the complement alternative pathway, CFH, represents the highest risk. As properdin (P) is also an important protein in this pathway, we analysed whether variants in the properdin gene (CFP) at Xp11.4 are associated with AMD. Ten exons of CFP were sequenced in a total of 222 Finnish patients with AMD (150 sporadic cases and 72 familial cases). The controls were 86 age-matched non-AMD patients with no large drusen and no or minimal focal pigmentary abnormalities. A total of four single nucleotide polymorphisms (SNPs) were detected in CFP, three of them infrequent (in 5 patients and controls in total). The fourth SNP, rs1048118 in exon 10, was more frequent, but was not associated with AMD, either alone (p=0.33) or in conjunction with other risk factors. Thus, CFP does not seem to confer any risk for AMD.