Figure 2.

A, Schematic representation of the RB protein. The black rectangles represent the A and B domains of the RB pocket, which is required for large T binding and for tumor suppression. The approximate locations of the missense mutations tested in this study are indicated. B, Activities of phenotypes. Null refers to the inactivating RB mutations that characterize familial retinoblastoma and selected common adult cancers. The DER is calculated as the sum of the number of eyes clinically involved with retinoblastoma, divided by the number of obligate carriers for each kindred, as described in the Subjects, Material, and Methods section. Clinical data sufficient to determine the mean DER score shown were available from only seven families (661W) or one family (712R). References for these kindreds are indicated in the Subjects, Material, and Methods section.