Identification of message from the CFH/CFHR3 hybrid gene. (A) Message for the hybrid CFH/CFHR3 gene was confirmed in cDNA using a forward primer (indicated by the forward arrow) in CFH exon 22 and a reverse primer (indicated by the reverse arrow) in CFHR3 exon 4. (B) Gel showing amplified cDNA. Lanes 1 and 2 show cDNA from IV:5 and V:4 (both affected persons) amplified using a forward primer in CFH exon 22 and a reverse primer in CFHR3 exon 4. Lane 3 shows normal control cDNA amplified with same primers. Lane 4 is a no DNA control. Lane 5 shows a size marker (kb). (C) cDNA sequence confirmed the presence of sequence consistent with a hybrid CFH/CFHR3 gene. (D) The protein product of the CFH/CFHR3 gene is a 24 SCR protein where SCRs 1 to 19 are derived from fH and SCRs 20 to 24 from CFHR3.