A 4-month-old boy is brought to the pediatrician by his parents who are concerned about a white dot on his right eye. Examination reveals a white pupillary reflex in his right eye. Imaging studies confirms the presence of a large tumor in the left eye that does not involve the optic nerve. It is diagnosed as the most common intraocular malignant tumor.
What is the chromosomal abnormality that could be present in this case?
A- Deletion of a gene on the affected chromosome
B- Duplication of a gene on the affected chromosome
C- Missing of a chromosome
D- Presence of an extra chromosome
E- Replication of a chromosome
This is most likely a case of retinoblastoma. Familial cases of retinoblastoma are associated with deletion of Rb gene on chromosome 13. These patients are also at risk of developing osteosarcoma as well.
The correct answer is A