A girl with unilateral retinoblastoma, mental retardation and several malformations was found to have an interstitial deletion 13q12 → q14. She was admitted to hospital at the age of 12 months because of a malformation of the left eye. She showed: psychomotor retardation, low hairline, bilateral epicanthic folds with hypertelorism, colobomata of the iris of the right eye, dental dysplasia, widespread nipples. Examination of the left eye showed behind the lens, a vascularized mass which became larger after 1 year, so it was enucleated because of a suspected retinoblastoma. The histologic examination confirmed the diagnosis. The patient died after a few months due to hepatic metastases. Chromosome analysis was performed on lymphocyte cultures, skin biopsy and tumoral cells from retinoblastoma tissue with Q, G and R bands. The parents had normal karyotypes. We confirm that loss of the 13q14 band is responsible for the predisposition to the retinoblastoma, while the other congenital abnormalities depend, in each case, upon the extent of the deletion. Retinoblastoma can be hereditary, sporadic or associated with the 13q deletion. A likely hypothesis to explain both the dominant mutation and the onset of the tumor associated with the deletion of the 13q14 band is haplo-insufficiency. By this hypothesis the deletion or mutation of a normal allele is insufficient for the normal function of the gene responsible for retinal development. The incomplete penetrance and expressivity in the hereditary transmission of the tumor should be found also in the cases with 13q14 deletion.
|Number of pages||5|
|Journal||Rivista Italiana di Pediatria|
|Publication status||Published - 1982|
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health