Definition of Retinoblastoma:

Retinoblastoma is a rare, cancerous tumor of a part of the eye called the retina.

Causes, incidence, and risk factors:

Retinoblastoma is caused by a mutation in a gene controlling cell division, causing cells to grow out of control and become cancerous.

In a little over half of the cases, this mutation develops in a child whose family has never had eye cancer.

Other times the mutation is present in several family members. If the mutation runs in the family, there is a 50% chance that an affected person's children will also have the mutation. They will therefore have a high risk of developing retinoblastoma themselves.

The cancer generally affects children under the age of 6. It is most commonly diagnosed in children aged 1 - 2 years.