a red eye.
leukocoria (white pupil)
Answer: D)leukocoria (white pupil)
Explanation: Leukocoria and strabismus are the most common presenting signs of retinoblastoma.
Retinoblastoma is the most common intraocular malignancy afflicting children.It occurs equally in males and females. On presentation, approximately 60% of cases are unilateral, and the remaining 40% are bilateral.Patients diagnosed with retinoblastoma are categorized by whether the mutation is germline or somatic. Patients with bilateral presentation are presumed to have germline mutations, and although most unilateral cases have somatic mutations, 15% of unilateral cases will still have germline mutations. Knudson described the “two-hit” mechanism for tumorigenesis in patients with retinoblastoma. Two active copies of the retinoblastoma gene are normally carried in human cells. Both copies must be mutated to lead to the development of retinoblastoma. The initial mutation inactivates one copy of the gene. This mutation may occur in somatic or germline cells. The second mutation occurs in somatic cells. In the majority of cases, this occurs through loss of heterozygosity.