FH and atypical hemolytic-uremic syndrome: In support of this, mutations in FH that affect the sialic acid recognition site have been associated with atypical hemolytic uremic syndrome (aHUS, a rare kidney disease also consequent on dysregulation of the AP),41 and genes encoding enzymes involved in sialic acid synthesis and processing have been reported to be differentially regulated in the placenta of women who develop pre‐eclampsia (see later).42, 43