April 2026 Research Update

This month, studies looking at enzyme replacement therapy (ERT) in Pompe disease added a clearer picture of why experiences with treatment can differ from person to person. In adults starting ERT, higher anti-drug antibody levels tended to go along with more infusion reactions, but did not clearly separate groups in walking or breathing results. In children identified early, a small series reported improved motor function after early ERT, while a single infant case highlighted how severe infusion reactions can dominate the course for some families. [1] [2] [3]

In 111 adults starting recombinant human GAA (rhGAA), people with high antibody titres had more infusion-associated reactions, meaning more problems during or shortly after infusions. When the researchers compared walking distance and lung function across antibody groups, they did not find broad differences that clearly separated the groups, even though a subset had antibodies with neutralizing activity (antibodies that may block the medicine from working). The most practical message from this study is that antibodies may be one reason some individuals have infusion issues or a less favorable course, even if the overall group comparisons look similar. [1]

In seven symptomatic children with late-onset Pompe disease found through newborn screening, early ERT was followed by motor improvement and normalization of creatine kinase (CK), a blood marker of muscle injury. The report also noted that children transitioned from alglucosidase alfa to avalglucosidase alfa without complications in this small group. Because this is a case series without a comparison group, it mainly shows what was observed in these children rather than proving what would happen for all children. [2]

A single case report described a CRIM-negative infant with infantile-onset Pompe disease who had repeated, severe infusion-associated reactions to ERT despite standard desensitization efforts. The authors reported using continuous epinephrine co-infusion with a low-concentration rhGAA infusion as a rescue approach to help prevent further reactions and allow ERT to continue. The child later died from a severe pulmonary infection at 15 months, underscoring that this report is about an exceptionally complex and high-risk situation and may not apply to most patients. [3]

For patients and caregivers, these studies help explain why ERT can be smooth for some people and difficult for others, especially around infusion reactions. The adult cohort suggests that anti-drug antibodies can matter for infusion safety and may matter for some individuals' disease course, even when group averages do not show big differences. The early-treated child series adds supportive real-world evidence that early treatment in symptomatic children identified by screening can coincide with improved motor function, while the single infant case highlights that rare, severe infusion reactions can require unusual approaches that are still not well studied. These findings mostly add understanding now, and they point to questions that need larger studies to confirm who is most affected by antibodies and which strategies best reduce infusion reactions. [1] [2] [3]

This month, newborn screening studies emphasized both what screening can achieve and what remains uncertain. Real-world program data from Italy showed that screening can identify late-onset Pompe disease in newborns, but also brings challenges like follow-up testing and uncertain genetic findings. An economic model from Japan suggested screening could increase lifetime quality-adjusted life years compared with clinical identification, yet the cost-effectiveness was highly dependent on assumptions like test costs, disease frequency, and treatment costs. [4] [5]

In Tuscany, Italy, a 10-year newborn screening program found 17 individuals labeled as late-onset Pompe disease among 234,642 screened infants. The program also reported a noticeable number of initial positive screens that required recall and second testing, and it identified novel genetic variants as well as pseudodeficiency and variants of uncertain significance (changes in a gene that may not cause disease, or whose meaning is not yet clear). This helps clarify that screening is not just about finding cases, but also about managing uncertainty and making sure confirmatory testing is strong. [4]

In Japan, a decision model comparing universal newborn screening with clinical identification for infantile-onset Pompe disease estimated an incremental cost-effectiveness ratio of 174 million JPY per quality-adjusted life year. The model projected more lifetime QALYs with screening than with clinical diagnosis, but it also showed that the result changed a lot depending on inputs like the screening test cost, the assumed disease prevalence, and the cost of enzyme replacement therapy. In plain terms, this study supports the idea that screening could improve outcomes in theory, while also showing why health systems may reach different conclusions when deciding whether screening is worth the cost. [5]

For families, these studies explain why newborn screening is often discussed as both promising and complicated. The Tuscany program shows that screening can find late-onset Pompe disease early, but it can also produce results that are not immediately clear and require extra follow-up to interpret. The Japan model suggests screening may improve lifetime health outcomes for infantile-onset Pompe disease, yet it does not settle the question of value because the answer shifts with costs and how rare the disease is. This information may matter more for future policy decisions and for understanding what a screening result can and cannot tell you right away, rather than changing anything immediately for an individual patient. [4] [5]

Studies focused on muscle changes this month pointed in the same direction: Pompe disease affects muscle biology early, and simple measurements may help track how it shows up in the body. In children with late-onset Pompe disease, lower muscle-related body composition measures went along with worse motor performance, and certain reported diet patterns tracked with walking distance and stomach symptoms. Separately, an early-stage patient-and-mouse study and a laboratory cell study both focused on lysosomes (the cell's recycling compartments), suggesting specific cell pathways that may become abnormal early and could eventually be used as research markers. [6] [7] [8]

In a study of 30 Chinese children with late-onset Pompe disease compared with 30 healthy children, the Pompe group had lower measures tied to muscle and overall body composition, including lower skeletal muscle mass. Several of these measures correlated with the 6-minute walk distance, and reported vegetable intake correlated with less severe gastrointestinal symptoms. Because this was a cross-sectional snapshot, it cannot show what causes what, but it supports the idea that nutrition and body composition differences may track with day-to-day function in some children. [6]

A translational study combining one asymptomatic patient with a novel GAA variant and Gaa-/- mice reported evidence of early glycogen buildup in muscle lysosomes along with increased levels of proteins linked to glycogen handling and lysosomes, including glycogenin. The authors suggested this pattern could be an early marker of muscle involvement before symptoms appear, but it needs confirmation in more people. This helps clarify that some muscle changes may begin quietly and could potentially be detected with future research tools. [7]

In laboratory cell models of Pompe disease, researchers reported that restoring lysosomal membrane integrity depended on fatty acid synthase and palmitic acid. This is early, preclinical work and does not predict patient outcomes, but it adds a specific biological clue about how damaged lysosomes might be repaired in cells. Over time, findings like this can help guide what pathways researchers test next. The experiments also showed persistent lysosomal membrane damage in cells from people with Pompe disease, and restoring the pathway the researchers studied improved lysosomal integrity and the cell's recycling functions in that laboratory model. [8]

For patients and caregivers, these studies mainly add understanding rather than immediate changes in care. The child body-composition study suggests that measures related to muscle mass and hydration can track with walking ability, and it raises the possibility that diet patterns relate to symptoms like stomach discomfort, though it does not prove that changing diet would change outcomes. The patient-and-mouse study suggests there may be measurable muscle changes even before symptoms, which could matter later if validated as a way to monitor early disease activity. The cell-model study is further from patient care, but it helps map out biological steps that may eventually lead to new tests or treatments if future research supports them. [6] [7] [8]

One study this month focused on how to assess diaphragm weakness in adults with late-onset Pompe disease, following 15 people over five years with several different breathing measurements. Sniff nasal inspiratory pressure and an ultrasound measure of diaphragm thickening declined earlier and more steeply than forced vital capacity, and both were more sensitive than forced vital capacity for picking up early breathing involvement. One patient developed symptomatic diaphragm weakness even though their forced vital capacity was preserved. [9]

For people living with late-onset Pompe disease, breathing strength and sleep-related breathing issues can be important parts of daily life, so careful measurement of diaphragm function is a meaningful research direction. Since no results were shared, this study does not yet clarify how common diaphragm problems are, how fast they change, or which tests best capture them. Its main value right now is as a sign that future reports may provide clearer ways to describe and track breathing-muscle involvement. [9]