Mode of transmission and intrafamilial phenotype variability of atypical hemolytic uremic syndrome: example from two families with heterozygous CFH mutation. CFH mutation: W1183R, SCR 20 (Family 1); W1183L, SCR 20 (Family 2). Notice i) the autosomal dominant (Family 1) or recessive (Family 2) mode of inheritance of the disease ii) the intrafamilial phenotype variability and incomplete penetrance in Family 1. Affected individuals are indicated with filled symbols. Deceased individuals are crossed. Carriers of the CFH mutation are indicated by an asterisk. Courtesy of Professor G. Deschênes (Hôpital Robert Debré, Paris), with permission.