Using polymerase chain reaction (PCR) amplification from blood samples
, Xbal and BamHl polymorphisms were analyzed in two families with bila
teral retinoblastoma. In one of the families it was predicted using th
e BamHl polymorphism that the 200 bp allele co-segregates with the dis
ease. This family was uninformative for Xbal polymorphism. The second
family was uninformative for both Xbal and BamHl polymorphism.