July 2026 Research Update

This month added clearer evidence that metachromatic leukodystrophy (MLD) can be linked to a higher chance of being hospitalized if someone gets COVID-19. Among hospitalized people with lysosomal disorders overall, one-year survival was similar to matched controls, although survival was not reported separately for MLD. This helps focus attention on the period when an infection is becoming serious enough to require hospital treatment. [1]

Using US electronic health record data from 2018 to 2024, researchers compared COVID-19 outcomes in people with lysosomal storage disorders to similar people without these disorders. They reported higher odds of COVID-19-related hospitalization for lysosomal storage disorders as a group, and MLD was one of the subtypes that still showed higher hospitalization odds after adjustment (OR 2.33). Among people who were hospitalized, one-year survival was very similar between the lysosomal storage disorder group and matched controls (82.1% vs 82.0%). [1]

For patients and caregivers, this primarily adds information about risk patterns rather than changing day-to-day care. It suggests that, in this dataset, the main difference for MLD showed up as a higher likelihood of hospitalization with COVID-19, while longer-term survival after hospitalization looked similar to people without these disorders. What remains uncertain is how much of the hospitalization difference is due to MLD itself versus other health conditions that may cluster with MLD, because this study looked at routine-care records rather than testing a specific prevention or treatment approach. [1]

This month, studies focused less on new outcomes and more on building the systems needed to find MLD earlier and to follow children carefully for years after advanced treatment. One report showed that a multi-step newborn screening approach can be run at scale, but also highlighted how often retesting may be needed and that no affected babies were found in the first year. A separate expert consensus laid out what comprehensive assessment and long-term monitoring could look like around autologous stem cell gene therapy, aiming for consistency across centers. [2] [3]

In Lombardy, Italy, a first-year newborn screening pilot used a three-tier process: a dried-blood-spot sulfatide test, then an ARSA enzyme activity test, and then whole-exome sequencing when needed. Among 16,130 screened newborns, no MLD cases were identified in the first year, and no infants were recalled, while a noticeable fraction needed repeat testing at earlier tiers (for example, 6.41% had duplicate retesting in the first tier). The study also reported that 33 newborns (0.20%) carried gene variants that could reduce ARSA activity, which matters because low enzyme activity can have causes other than MLD and can complicate screening results. [2]

A European expert group described consensus recommendations for children with MLD who receive autologous hematopoietic stem and progenitor cell gene therapy (a treatment that uses a person's own blood-forming stem cells after adding a working gene). The document covers steps before treatment (including rapid diagnostic confirmation and baseline neurologic and developmental checks), the treatment phase itself (including stem cell collection and busulfan conditioning), and a structured long-term follow-up plan that includes imaging and lab surveillance. It also emphasizes long-term data collection and biobanking for at least 15 years so outcomes and late effects can be tracked more consistently. [3]

For families, these studies mainly matter as building blocks for earlier diagnosis and more standardized long-term tracking, rather than as direct evidence that outcomes are better this month. The newborn screening pilot helps clarify what a real-world screening pathway might involve, including the practical issue that some babies may need retesting and follow-up to sort out borderline results, even when no MLD cases are found in the first year. The consensus recommendations may matter now for families already pursuing gene therapy because they describe what kinds of assessments and long-term monitoring programs are being planned, but they are expert guidance rather than proof of benefit from a new trial. [2] [3]