[Retinoblastoma and transmission of balanced chromosomal modifications].

Two cases of retinoblastoma in two children showing a chromosomal rearrangement in the karyotype were reported. In the first case, a pericentric inversion of chromosome 9 was observed both in the child and his father. In the second case, a reciprocal translocation t (3;12)(q29;q15) present also in the paternal karyotype was identified. A strict connection cannot be established between the tumour itself and the family chromosomal aberrations, but these observations raise the problem of a possible "interchromosomal effect".