In a case where a 2-month-old is observed without a red reflex in one eye, which chromosome is likely expressing an abnormality?

In a case where a 2-month-old is observed without a red reflex in one eye, which chromosome is likely expressing an abnormality?

• A. 21
• B. 13
• C. 22
• D. 18

Answer: (B)

When a 2-month-old child is observed without a red reflex in one eye, it raises concern for conditions such as retinoblastoma, a type of eye cancer that typically affects young children. Retinoblastoma is associated with mutations in the RBP1 gene located on chromosome 13. This gene plays a crucial role in the regulation of cell division and the development of the retina. An absence of the red reflex can indicate that there is an opacity in the optical pathway, which is often caused by the tumor. Identifying a potential tumor at an early age is vital for prognosis, as early intervention can significantly improve outcomes. In the context of genetic abnormalities linked to retinoblastoma, chromosome 13 is critical due to its association with hereditary forms of the disease. Mutations or deletions in this region can lead to a predisposition to developing retinoblastoma, reinforcing the likelihood that abnormalities in chromosome 13 are expressed in conditions where the red reflex is absent. This understanding of retinoblastoma and its genetic associations underlines why the presence of an abnormality on chromosome 13 is the most relevant in this scenario.

When a 2-month-old child is observed without a red reflex in one eye, it raises concern for conditions such as retinoblastoma, a type of eye cancer that typically affects young children. Retinoblastoma is associated with mutations in the RBP1 gene located on chromosome 13. This gene plays a crucial role in the regulation of cell division and the development of the retina.

An absence of the red reflex can indicate that there is an opacity in the optical pathway, which is often caused by the tumor. Identifying a potential tumor at an early age is vital for prognosis, as early intervention can significantly improve outcomes.

In the context of genetic abnormalities linked to retinoblastoma, chromosome 13 is critical due to its association with hereditary forms of the disease. Mutations or deletions in this region can lead to a predisposition to developing retinoblastoma, reinforcing the likelihood that abnormalities in chromosome 13 are expressed in conditions where the red reflex is absent.

This understanding of retinoblastoma and its genetic associations underlines why the presence of an abnormality on chromosome 13 is the most relevant in this scenario.