Medical Genetics Tumors are hereditary Hereditary retinoblastoma is an autosomal dominant trait in which susceptibility to retinoblastoma is inherited. This is an unusual dominant trait in that a mutation in one rb gene is not sufficient to cause symptoms, but mutations in the second allele often arise during developmentMedical Genetics Tumors are hereditary Hereditary retinoblastoma is an autosomal dominant trait in which susceptibility to retinoblastoma is inherited. This is an unusual "dominant" trait in that a mutation in one RB gene is not sufficient to cause symptoms, but mutations in the second allele often arise during development