Epidemiology

Etiology

The retinoblastoma gene (Rb) is a tumor suppressor gene found on chromosome 13.

Heritable retinoblastomas (autosomal dominant inheritance)
- Two-hit hypothesis
- Inherited retinoblastomas tend to be bilateral.
  - Since all retinal cells have already lost one allele and the probability of losing the second allele in both eyes is quite high
- Have a significantly higher risk of developing osteosarcomas and pinealomas.
  - They are also caused by mutations of Rb gene.
Sporadic retinoblastomas: due to spontaneous mutation →
- Two spontaneous mutations must occur in the same retinal cell, affecting both Rb alleles.
- Sporadic retinoblastomas tend to be unilateral