Inherited metabolic disorders
Late-infantile metachromatic leukodystrophy
Late-infantile metachromatic leukodystrophy is a rapidly progressive early-childhood disorder, usually caused by ARSA deficiency. Accumulated sulfatides damage the insulating myelin around nerves, affecting movement and other neurologic functions.
Other names and abbreviations
LI-MLD · late-infantile MLD · ARSA deficiency · metachromatic leukodystrophy · MLD · Late-infantile arylsulfatase A deficiency · Early-onset metachromatic leukodystrophy, late-infantile form
Where transplant fits
Approved autologous gene therapy can be used for specified children before symptoms begin and requires no registry donor. Conventional allogeneic transplantation is generally not recommended for this rapidly progressive form because its effect develops too slowly.
Treatment depends on the exact diagnosis, disease stage, prior treatment and the person’s health. These categories are not estimates of donor demand.
Treatment at a glance
- Who it affects
- The late-infantile form becomes symptomatic in early childhood; a family diagnosis can sometimes identify an affected sibling before symptoms.
- Other treatment options
- In eligible presymptomatic children, gene therapy is a time-sensitive specialist pathway. Supportive neurologic, feeding, respiratory and comfort care address the needs of symptomatic children.
- Cells used for transplantation
- The patient’s own gene-modified stem cells for eligible gene therapy. A registry donor is not required for this treatment.
Why the details matter
The presymptomatic gene-therapy indication must not be generalized to symptomatic late-infantile MLD. Stem-cell treatment cannot be assumed to reverse established neurologic injury.
Questions to bring to your care team
What is the exact diagnosis or subtype? What is the goal of each treatment option? If transplant is being considered, why does it fit this situation, which cells would be used and what are the alternatives?
Sources and further reading
- Arylsulfatase A Deficiency
GeneReviews, University of Washington / NCBI Bookshelf · Accessed 2026-09-05 - LENMELDY: indication and current prescribing information
FDA · Accessed 2026-09-05 - Inborn Errors of Metabolism and Osteopetrosis
EBMT Handbook · 2024-04-11
Understanding can become action.
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