E75.25

HCC Category Mapping

What This Code Means

Metachromatic leukodystrophy is a rare inherited metabolic disorder affecting the nervous system where the body cannot break down certain fatty substances in nerve cells, leading to progressive loss of neurological function and demyelination.

Coding Tips

• •Document the form of metachromatic leukodystrophy if specified (late infantile, juvenile, or adult) as this affects disease progression
• •Code associated neurological manifestations such as developmental regression, seizures, or motor decline separately if documented

Clinical Significance

Metachromatic leukodystrophy is a severe lysosomal storage disorder caused by arylsulfatase A deficiency, leading to progressive demyelination of the central and peripheral nervous systems. The late infantile form is most common, causing rapid motor and cognitive decline, while juvenile and adult forms progress more slowly. Gene therapy (atidarsagene autotemcel) has recently been approved for pre-symptomatic patients.

Documentation Requirements

• ✓Confirmed diagnosis of metachromatic leukodystrophy
• ✓Arylsulfatase A enzyme assay showing deficiency
• ✓ARSA gene mutation analysis
• ✓Form specification: late infantile, juvenile, or adult onset
• ✓Brain MRI showing white matter demyelination pattern
• ✓Nerve conduction studies documenting peripheral neuropathy
• ✓Treatment status including gene therapy eligibility assessment

Commonly Confused Codes