Chromosome 13 deletion syndrome: report of a new case and discussion of the different etiologic patterns of retinoblastoma.

A partial monosomy 13 by interstitial deletion was found in the complement of a patient with mental retardation and mild dysmorphic features. Due to the involvement of band q14 in the deletion, an ocular investigation was performed which showed the presence of a retinoblastoma in a preclinical stage. The different patterns of retinoblastoma inheritance are discussed and the importance of an accurate clinical investigation is stressed in all cases in whom chromosomal aberration is known to be associated with neoplasias.