**Core Concept**
The child's presentation of seizures, oval hypopigmented macules, and sub-normal IQ suggests a neurocutaneous disorder involving both the skin and the nervous system. This condition is characterized by the presence of skin lesions and neurological abnormalities, often due to a genetic defect affecting cell migration and differentiation.

**Why the Correct Answer is Right**
The condition described is likely Tuberous Sclerosis Complex (TSC), a genetic disorder caused by mutations in either the TSC1 or TSC2 genes. These genes encode for the protein subunits of the TSC complex, which regulates the activity of the mechanistic target of rapamycin (mTOR) pathway. The mTOR pathway is crucial for cell growth, proliferation, and survival. In TSC, the mTOR pathway is constitutively activated, leading to the development of benign tumors (hamartomas) in multiple organs, including the skin, brain, and kidneys. The oval hypopigmented macules, also known as ash-leaf spots, are characteristic skin lesions in TSC. The seizures and sub-normal IQ are due to the presence of cortical tubers, subependymal giant cell astrocytomas, and other brain lesions.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Neurofibromatosis Type 1 (NF1) typically presents with café-au-lait macules, not oval hypopigmented macules.

**Option B:** This option is incorrect because Sturge-Weber syndrome is characterized by a port-wine stain on the face, seizures, and developmental delay, but it does not typically present with oval hypopigmented macules.

**Option C:** This option is incorrect because tuberous sclerosis complex (TSC) is a distinct clinical entity from neurofibromatosis type 2 (NF2), which typically presents with bilateral vestibular schwannomas and cataracts.

**Clinical Pearl / High-Yield Fact**
The ash-leaf spots in TSC are often visible on Wood's lamp examination, which emits ultraviolet light that makes the lesions appear more prominent. This is a classic clinical correlation that can aid in the diagnosis of TSC.

**Correct Answer:** C. Tuberous Sclerosis Complex (TSC)