**Core Concept**
Wilms tumor, also known as nephroblastoma, is a type of kidney cancer that primarily affects children. The condition is characterized by the presence of an abdominal mass, hemihypertrophy, and genitourinary anomalies. The genetic basis of Wilms tumor involves mutations in the WT1 gene, which plays a crucial role in kidney development and function.

**Why the Correct Answer is Right**
The WT1 gene is a tumor suppressor gene that regulates cell growth and division in the developing kidneys. Mutations in the WT1 gene can lead to the development of Wilms tumor. The gene is located on the short arm of chromosome 11 (11p13). The WT1 gene is essential for the normal development of the kidneys, and mutations in this gene can result in the formation of a Wilms tumor. The presence of an abdominal mass, polyuria, and polydipsia in the child, along with the IVP revealing a streaky appearance of the kidneys, are indicative of Wilms tumor.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the WT1 gene is not located on chromosome 1.
**Option B:** This option is incorrect because the WT1 gene is not associated with neuroblastoma.
**Option C:** This option is incorrect because the WT1 gene is not located on chromosome 16.

**Clinical Pearl / High-Yield Fact**
Wilms tumor is often associated with other congenital anomalies, such as aniridia, hemihypertrophy, and genitourinary anomalies. The presence of these anomalies should raise suspicion for Wilms tumor, especially in children with an abdominal mass.

**Correct Answer:** D