We describe the facial dysmorphic phenotype and the neurological development of a series of 22 retinoblastoma patients sharing a cytogenetically detectable 13q deletion in a retrospective and longitudinal study. In most of the cases, high-resolution banding analysis, morphological analysis, and assessment for neurodevelopmental outcome, as well for organ malformations, were performed.
Chromosomal rearrangement involving the RB1 gene included 20 13q interstitial deletions (including 16 de novo deletions) and two de novo translocations. The most prominent dysmorphic abnormalities were anteverted ear lobes (90%), a high and broad forehead (85%), and a prominent philtrum (65%). This phenotype was associated with severe mental retardation and/or motor impairment at age 2 years in 69% of patients and correlated with the size and the location of the 13q deletion. The survival rate of our series (91%) was not different from that usually seen in retinoblastoma patients.