**Question:** All are seen in metachromatic leukodystrophy EXCEPT:

A. Hyperintensity on T2-weighted MRI
B. Sphingolipid accumulation
C. Progressive spasticity
D. Cognitive impairment

**Core Concept:** Metachromatic Leukodystrophy (MLD) is a rare hereditary disorder caused by a deficiency of the arylsulfatase A enzyme, which plays a crucial role in the breakdown of sulfatides (sphingolipids) in the central nervous system (CNS). This deficiency leads to the accumulation of sulfatides and other sphingolipids, causing damage to the myelin sheaths and neurons, leading to neurological deficits and progressive neurological deterioration.

**Why the Correct Answer is Right:**

Correct Answer: **D. Cognitive impairment**

In MLD, the primary neurological symptoms are related to the accumulation of sphingolipids, primarily in the CNS, leading to damage to the myelin sheaths and neurons. The cognitive decline is not the main symptom in MLD, as the primary focus of the disease is on motor and sensory symptoms. Therefore, cognitive impairment is not typically seen in MLD and is not considered as a typical feature of the disease.

**Why Each Wrong Option is Incorrect:**

A. **Hyperintensity on T2-weighted MRI**: This is a common finding in MLD, as the accumulation of sphingolipids causes focal lesions in the white matter of the brain, leading to increased signal intensity on T2-weighted MRI.

B. **Sphingolipid accumulation**: As mentioned earlier, MLD is characterized by the accumulation of sphingolipids, which is consistent with the disease process.

C. **Progressive spasticity**: Spasticity is a common neurological manifestation of MLD due to the damage to the myelin sheaths and neurons.

D. **Cognitive impairment**: As explained earlier, cognitive impairment is not a primary feature of MLD, as the disease primarily affects motor and sensory functions.

**Clinical Pearl:** Metachromatic Leukodystrophy is a disorder characterized by the accumulation of sulfatides and other sphingolipids due to a deficiency of arylsulfatase A enzyme. The disease primarily affects the CNS, leading to progressive neurological deficits, including spasticity and motor and sensory symptoms. MRI findings, including hyperintensity on T2-weighted sequences, are highly specific for MLD diagnosis.