# Metachromatic Leukodystrophy Presenting with Multiple Cranial Nerve and Lumbosacral Nerve Root Enhancement Without White Matter Changes

## TL;DR

A rare case of metachromatic leukodystrophy was identified in a child with cranial nerve issues before typical brain changes appeared.

## Contribution

This case highlights a unique early presentation of MLD with cranial nerve enhancement and ataxia, preceding white matter changes.

## Key findings

- A 20-month-old patient showed cranial nerve enhancement on MRI without white matter changes.
- Follow-up MRI revealed new white matter changes consistent with leukodystrophy.
- Genetic testing confirmed metachromatic leukodystrophy due to a homozygous ARSA variant.

## Abstract

Background: Metachromatic leukodystrophy (MLD) is a rare autosomal recessive disorder that causes demyelination of both the central (CNS) and peripheral nervous systems (PNS). Objective: This study aims to report a unique MLD case presenting with cranial neuropathies and ataxia, initially without white matter changes on MRI, leading to diagnostic uncertainty. Results: A 20-month-old presented with bilateral abduction deficits, facial diplegia, and ataxia, raising the possibility of an acquired demyelinating condition. An MRI scan showed the enhancement of multiple cranial nerves, but normal white matter. A follow-up MRI showed new white matter changes that spared the U-fibers, suggesting a leukodystrophy. Biochemical assays were suggestive of metachromatic leukodystrophy, which was confirmed with genetic testing demonstrating a homozygous c.848+3A > G variant in ARSA. Conclusions: Our patient suggests that the initial presentation of MLD may mimic an acquired demyelinating condition and manifest with multiple cranial nerve palsies before more typical white matter changes evolve.