A child presented to the casualty with seizures. On examination an oval hypopigmented macules were noted on the trunk, along with sub-normal IQ. Probable diagnosis of the child is:
**Core Concept**
Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the growth of non-cancerous tumors in various parts of the body, including the brain, skin, and organs. This condition is associated with mutations in either the TSC1 or TSC2 gene, leading to the activation of the mammalian target of rapamycin (mTOR) pathway and subsequent cellular proliferation.
**Why the Correct Answer is Right**
The clinical presentation of seizures, oval hypopigmented macules (ash-leaf spots), and sub-normal IQ is highly suggestive of tuberous sclerosis complex. The ash-leaf spots are a classic skin manifestation of TSC, resulting from the loss of melanocytes in the epidermis. The seizures are often due to the presence of cortical tubers, which are abnormal brain tissue formations that can cause seizures and developmental delays. The sub-normal IQ is likely due to the presence of brain lesions, including subependymal giant cell astrocytomas, which can cause cognitive impairment.
**Why Each Wrong Option is Incorrect**
**Option A:** Neurofibromatosis type 1 (NF1) is characterized by café-au-lait macules, neurofibromas, and optic gliomas, but it does not typically present with seizures and sub-normal IQ in the context of hypopigmented macules.
**Option B:** Sturge-Weber syndrome is characterized by a port-wine stain, seizures, and developmental delays, but it does not typically present with hypopigmented macules.
**Option C:** Incontinentia pigmenti is characterized by Blaschko's lines, seizures, and developmental delays, but it does not typically present with hypopigmented macules.
**Clinical Pearl / High-Yield Fact**
Tuberous sclerosis complex is a genetic disorder that can be diagnosed prenatally or postnatally through genetic testing or imaging studies. The presence of ash-leaf spots, seizures, and sub-normal IQ should raise suspicion for TSC.
**Correct Answer:** C. Tuberous sclerosis complex.