ERT may help improve bone health for male Fabry patients: Study

Male patients tend to have lower bone density than their female counterparts

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Enzyme replacement therapy (ERT) can help to increase the bone density of male patients with Fabry disease, who tend to have lower bone mineral density, a study has found.

Female patients, by contrast, were found generally not to have low bone density, and ERT did not substantially change their measures.

The study, “Investigation of bone mineral density and the changes by enzyme replacement therapy in patients with Fabry disease,” was published in Molecular Genetics and Metabolism.

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Study included 15 people with Fabry disease

In Fabry disease, symptoms are caused by the toxic buildup of fatty molecules such as globotriaosylsphingosine (lyso-Gb3), which causes damage to the body’s organs. The ways in which Fabry affects some organs, such as the kidneys and heart, are well-documented. However, there’s been less research into whether and how bones are affected by Fabry.

In the study, scientists in Japan analyzed data for 15 people with Fabry disease who were seen at their center, all of whom underwent standardized assessments to measure bone mineral density (BMD) in the lower spine and pelvis. As the term suggests, BMD measures how dense and tough the bones are.

Among the 15 patients in the study, seven were male and eight were female; male patients had significantly higher levels of lyso-Gb3 in their blood. Two of the patients had already started on ERT prior to being seen at the center, and the other 13 were subsequently started on Fabrazyme or Replagal.

Results showed that the male patients tended to have notably lower BMD than their female counterparts. Comparisons against normative data suggested that, for most of the male patients, BMD was lower than would be expected in the general population. By contrast, for female patients, BMD was generally similar to or slightly higher than normative values.

Analyses including all 15 patients showed a significant negative correlation between BMD and lyso-Gb3. In other words, patients with higher levels of the disease biomarker tended also to have less-dense bones. In sex-stratified analyses, the association between BMD and lyso-Gb3 was significant in male patients, but not in female patients.

Available data from patients who started on ERT at the clinic showed a significant reduction in lyso-Gb3 levels for all patients after starting on treatment, though the magnitude of this decrease was generally more dramatic in male patients.

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In male patients, bone mineral density tended to increase after starting ERT

Among male patients, BMD tended to increase after starting ERT. For the female patients, bone density remained largely stable after starting treatment.

These data indicate that “ERT could be a crucial treatment to maintain bone health in male [Fabry disease] patients,” the researchers wrote.

Statistical analyses showed that, among male patients, those who experienced a larger reduction in lyso-Gb3 levels also tended to experience a greater improvement in bone density. These data suggest that fatty molecules like lyso-Gb3 may build up in bone tissue to drive bone damage in Fabry disease, the researchers said.

The scientists noted that this study is limited by its small size and single-center nature, stressing a need for further investigation to understand how bones are affected in Fabry and how this might be addressed with therapies.