Figure 1. Pedigree of Family 1 and Family 2. Pedigree of the Family 1 in which the L42RfsX25 truncating mutation segregates is presented. Alternative translation might be the mechanism by which different level of expressivity are present within this family ranging from bilateral RB to unilateral retinomas. In Family 2 which includes an unaffected R46K mutation carrier, the level of expressivity is even lower. This mutation has been previously reported. Solid black symbols represent bilateral retinoblastoma (RB). Half black symbols represent unilateral RB. Solid gray symbols represent bilateral retinoma. Half gray symbols represent unilateral retinoma. The slashed symbol represents deceased individual, and symbol with a black dot represents an unaffected mutation carrier.