A 2-year-old child is brought by parents who noticed a white pupillary reflex in the right eye on photographs taken with flash. Examination shows leukocoria and strabismus. CT shows an intraocular calcified mass. Mutation in which gene is most commonly implicated?

• A APC tumor suppressor gene
• B NF1 tumor suppressor gene
• C WT1 tumor suppressor gene
• D RB1 tumor suppressor gene ✓

Explanation

Retinoblastoma is the commonest intraocular malignancy of childhood and typically presents before age 3 with leukocoria, strabismus, or secondary glaucoma. Calcification within the mass on imaging is characteristic. It follows the two hit model of Knudson, arising from inactivation of both alleles of the RB1 tumor suppressor gene on chromosome 13q14. WT1 relates to Wilms tumor, APC to familial polyposis, and NF1 to neurofibromatosis type 1.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.