Metachromatic leukodystrophy (MLD) is a rare inherited disorder that progressively damages the nervous system, leading to loss of motor and cognitive functions. Caused by a deficiency of the enzyme arylsulfatase A, MLD results in the accumulation of sulfatides in cells, particularly affecting the brain and spinal cord. The disease manifests in three forms - late infantile, juvenile, and adult - with varying onset ages and symptoms, ranging from difficulty walking and speech impairment to behavioral changes and dementia.