I know this is nearly 10 years later, but...
My father (Patrick C Doran), his sister both had RP.
His cousins (1 male and 1 female) also had RP
This came about because a brother and sister (Doran) married a brother and sister - and clearly both were carrying the recessive RP gene. I suspect this may link us. We don't know when our ancestor arrived in Australia. We don't have info on his siblings or parents. His name was Patrick Doran, we think he came from County Armagh. I don't have all the info with me now re birth / death but can get back to you if we think there is a connection.