<prompt> Hereditary retinoblastomas develop from the following chromosomal deletion?13 q1413 p1414 p1314 q13  <response>: Retinoblastoma RB gene has been identified as 14 band on the long-arm of chromosome 13 13q14 and is a cancer suppressor or antioncogenic gene.Deletion or inactivation of this protective gene by two mutations Knudsons two-hit hypothesis results in the occurrence of retinoblastoma.Ref: Khurana; Comprehensive ophthalmology; 4th edition; Page no: 280 