Retinoblastoma is a rare type of eye cancer that typically affects young children, usually before the age of 5. It originates in the retina, the layer of light-sensitive tissue at the back of the eye.

Retinoblastoma is usually caused by a mutation in the RB1 gene, which is a tumor suppressor gene. This gene normally produces a protein that helps to control cell growth by preventing cells from dividing too rapidly or in an uncontrolled way. When the RB1 gene is mutated, the protein it produces may not function properly, leading to uncontrolled cell growth and the development of a tumor.

There are two forms of retinoblastoma:

1. Heritable Retinoblastoma: This form is caused by a germline mutation in the RB1 gene, meaning the mutation is present in all cells of the body from birth and can be passed on from parent to child. Children with a germline mutation have a higher risk of developing retinoblastoma in both eyes (bilateral retinoblastoma) and may also have an increased risk of developing other types of cancer later in life.
2. Non-Heritable Retinoblastoma: This form is caused by a somatic mutation in the RB1 gene, meaning the mutation occurs in a single retinal cell during the child’s development and is not inherited from the parents or passed on to the child’s offspring. Children with a somatic mutation typically develop retinoblastoma in one eye only (unilateral retinoblastoma).

Common symptoms of retinoblastoma include a visible whiteness in the pupil when light is shone in the eye (often seen in photos taken with a flash), crossed or misaligned eyes, and changes in the color of the iris. Treatment for retinoblastoma can include chemotherapy, radiation therapy, laser therapy, cryotherapy, and surgery to remove the eye (enucleation) in more advanced cases.

With early detection and appropriate treatment, the majority of children with retinoblastoma can be cured, though they may have vision loss or other long-term effects depending on the extent and location of the tumor and the treatments used. Regular follow-up care is crucial, as there is a risk of the cancer returning or of new cancers developing, particularly in children with the heritable form of retinoblastoma.