Identification of a rare coding variant in complement 3 associated with age-related macular degeneration.
Zhan X., Larson DE., Wang C., Koboldt DC., Sergeev YV., Fulton RS., Fulton LL., Fronick CC., Branham KE., Bragg-Gresham J., Jun G., Hu Y., Kang HM., Liu D., Othman M., Brooks M., Ratnapriya R., Boleda A., Grassmann F., von Strachwitz C., Olson LM., Buitendijk GHS., Hofman A., van Duijn CM., Cipriani V., Moore AT., Shahid H., Jiang Y., Conley YP., Morgan DJ., Kim IK., Johnson MP., Cantsilieris S., Richardson AJ., Guymer RH., Luo H., Ouyang H., Licht C., Pluthero FG., Zhang MM., Zhang K., Baird PN., Blangero J., Klein ML., Farrer LA., DeAngelis MM., Weeks DE., Gorin MB., Yates JRW., Klaver CCW., Pericak-Vance MA., Haines JL., Weber BHF., Wilson RK., Heckenlively JR., Chew EY., Stambolian D., Mardis ER., Swaroop A., Abecasis GR.
Macular degeneration is a common cause of blindness in the elderly. To identify rare coding variants associated with a large increase in risk of age-related macular degeneration (AMD), we sequenced 2,335 cases and 789 controls in 10 candidate loci (57 genes). To increase power, we augmented our control set with ancestry-matched exome-sequenced controls. An analysis of coding variation in 2,268 AMD cases and 2,268 ancestry-matched controls identified 2 large-effect rare variants: previously described p.Arg1210Cys encoded in the CFH gene (case frequency (fcase) = 0.51%; control frequency (fcontrol) = 0.02%; odds ratio (OR) = 23.11) and newly identified p.Lys155Gln encoded in the C3 gene (fcase = 1.06%; fcontrol = 0.39%; OR = 2.68). The variants suggest decreased inhibition of C3 by complement factor H, resulting in increased activation of the alternative complement pathway, as a key component of disease biology.