Cross-phenotype association mapping of the MHC identifies genetic variants that differentiate psoriatic arthritis from psoriasis.
John David BowesJames AshcroftNick DandFarideh Jalali-NajafabadiEftychia BellouPauline HoHelena Marzo-OrtegaPhilip S HelliwellMarie FeletarAnthony W RyanDavid J KaneEleanor KorendowychMichael A SimpsonJonathan PackhamRoss McManusMatthew A BrownCatherine H SmithJonathan N BarkerNeil McHughOliver FitzGeraldRichard B WarrenAnne BartonPublished in: Annals of the rheumatic diseases (2017)
By controlling for the age of psoriasis onset, we show, for the first time, that HLA-C*06:02 is not associated with PsA and that amino acid position 97 of HLA-B differentiates PsA from PsC. This amino acid also represents the largest genetic effect for ankylosing spondylitis, thereby refining the genetic overlap of these two spondyloarthropathies. Correcting for bias has important implications for cross-phenotype genetic studies.