[Interstitial deletion of the long arms of chromosome 13]

We present a case of a child with important phenotypic abnormalities (retinoblastoma, hypoplasia of the thumbs and genital), as well as craneofacial and evident psychomotor retardation. The chromosomal study showed a interstitial delection of the long arms of a chromosome from D group. We try to correlate karyotypes and phenotype, telling about difficulties that this relation means insisting about the importance of knowing more cases of chromosome 13 delection. We also think that subbands analysis represents an important factor in this correlation.