General description

Metachromatic leukodystrophy (MLD) is an autosomal recessive disorder caused by a deficiency of arylsulfatase A, leading to the accumulation of sulfatides and subsequent demyelination in the cerebral white matter, peripheral nerves, and kidneys. MLD can be classified into infantile, juvenile, and adult forms based on age of onset and symptoms.

The infantile form is the most common, typically developing by 2 years of age, and presents with hypotonia, intellectual regression, optic atrophy, spastic paralysis, peripheral neuropathy, and increased cerebrospinal fluid protein. The juvenile form develops between ages 4 to 10, with a slower progression but similar symptoms. The adult form usually appears in the late teens or 20s to 30s, characterized by psychiatric symptoms (e.g., schizophrenia-like behavior), progressive dementia, and peripheral neuropathy. It can be mistaken for multiple sclerosis, and symptoms such as decreased concentration, intellectual decline, and urinary incontinence may also be seen initially.