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Metachromatic Leukodystrophy (MLD) rapidly progresses, increasing the urgency for early diagnosis1,2

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Actor portrayal.

Metachromatic Leukodystrophy (MLD) rapidly progresses, increasing the urgency for early diagnosis1,2

MLD is first suspected by recognizing the characteristic pattern of progressive impairment3

Newborn screening is critical in ensuring that newborns are diagnosed and treated effectively before they become symptomatic and progression begins.4 If there is any suspicion of MLD based on suggestive clinical symptoms, refer to a specialist for confirmatory lab testing to rule out MLD.1
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Biochemical testing can reveal the presence of MLD; genetic testing can confirm the diagnosis.1

Biochemical tests include urine sulfatide testing and ARSA enzyme activity testing. Genetic tests include gene sequencing for the ARSA gene variant.1

Magnetic resonance imaging (MRI) can also confirm a diagnosis of MLD, because it can show the presence and absence of myelin.3

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MLD is rare, progressive, and fatal if left untreated. When diagnosed, there isn’t a moment to lose.5 Refer your patient to a specialized treatment center familiar with the treatment of MLD.

Hear from one mother’s initial reactions to her daughter’s MLD diagnosis
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References: 1. Wang RY, Bodamer OA, Watson MS, et al. Lysosomal storage diseases: diagnostic confirmation and management of presymptomatic individuals. Gen Med. 2011;13:457-484. 2. Chang SC, Eichinger CS, Field P. The natural history and burden of illness of metachromatic leukodystrophy: a systematic literature review. Eur J Med Res. 2024;29:181. 3. Metachromatic leukodystrophy. National Institute for Rare Disorders. Accessed April 17, 2025. https://rarediseases.org/rare-diseases/metachromatic-leukodystrophy/#diagnosis 4. Fumagalli F, Calbi V, Natali Sora MG, et al. Lentiviral haematopoietic stem-cell gene therapy for early-onset metachromatic leukodystrophy: long-term results from a non-randomised, open-label, phase 1/2 trial and expanded access. Lancet. 2022;399:372-383. 5. Biffi A, Cesani M, Fumagalli F, et al. Metachromatic leukodystrophy-mutation analysis provides further evidence of genotype-phenotype correlation. Clin Genet. 2008;74:349-357.