Jada Bascom Foundation
All conditions

Inherited metabolic disorders

Late-juvenile metachromatic leukodystrophy

Also called: LJ-MLD · late-juvenile MLD · ARSA deficiency · metachromatic leukodystrophy · MLD · Late-juvenile arylsulfatase A deficiency · Late-onset juvenile metachromatic leukodystrophy

What a donor has to do with this

For some people with this condition, a transplant using blood stem cells from an unrelated donor is part of the treatment guidelines. When a transplant is the right route and no one in the family matches, that donor comes from a registry. Not everyone with this condition has a transplant, and many never need one.

This is our reading of published transplant guidelines for this condition, not a measurement of how many people need a donor. Where a source actually counted donors, the figure and the people it counted are shown further down. Where none did, we say so rather than estimate.

What the evidence says

Who it affects
Typical onset/diagnosis: late-juvenile MLD begins after the early-juvenile window and before adult-onset disease, usually in later school age or adolescence. Evidence: German 12-child transplanted and 35-child comparison cohorts (published 2020) plus U.S. NIH GARD (updated 2026); no markedly enriched population was identified.
Treatments other than a transplant
Supportive neurologic, rehabilitative, and palliative care — standard noncurative management — multiple regions — Approved Lenmeldy/Libmeldy indications do not extend to late-juvenile MLD.
If a transplant is used, the cells come from
bone marrow: used; mobilized peripheral blood stem cells: rarely used in lysosomal-storage-disease HCT guidance; umbilical cord blood: frequently used and may be preferred to bone marrow; dominance: umbilical cord blood is the preferred source in the opened EBMT lysosomal-storage-disease guidance
How often the donor was unrelated
Not reported. No source we could read states this for this condition, so we do not give a number. An estimate here would be a guess dressed as evidence.

Where this gets complicated

The 2016 German cohort included 24 transplanted and 41 nontransplanted patients; 5-year survival after HSCT was 79% (19 of 24).; In that 2016 German cohort, stable outcome was associated with early disease, IQ at least 85, gross-motor level 0–1, and low MRI burden.; The early/late juvenile cut point varies across sources; this row uses onset after age 6 through before adult onset, consistent with the 2020 German cohort definition.

Written for transplant clinicians, not for patients. We quote it so you can see what the guidance actually says:
“Transplantation at a presymptomatic or early symptomatic stage of juvenile MLD is associated with a reasonable chance for disease stabilization.”

It describes what teams consider in general. It cannot say what applies to any one person. Read the source.

People with this condition need donors

Joining a registry is a cheek swab and a short health form. You are contacted only if you turn out to be a possible match for someone, and you can ask questions and decline before anything else happens.

Find your registry

Related conditions

Others in inherited metabolic disorders. They are genuinely different diseases with different treatments — the group name is not a diagnosis.

Where this came from