This clinical trial is focused on studying a rare genetic disorder called PMM2-CDG, which stands for Phosphomannomutase 2 Congenital Disorder of Glycosylation. This condition affects the body’s ability to properly process certain sugars, leading to a variety of health issues. The study involves a treatment called GLM101, which is administered through an injection or infusion directly into the bloodstream. GLM101 contains a substance known as alfa-d-mannopyranosyl phosphate dipotassium, which is designed to help manage the symptoms of PMM2-CDG.

The purpose of this study is to examine the safety of GLM101 in patients who have previously received this treatment. Participants will receive GLM101 over a period of time, and their health will be monitored to gather information on any side effects or changes in their condition. The study will also look at how the treatment affects certain symptoms of PMM2-CDG, such as coordination and balance issues, which are measured using a tool called the International Co-operative Ataxia Rating Scale (ICARS). Additionally, the study will measure the levels of a sugar called Mannose-1-Phosphate in the blood, which is a component of GLM101.

Throughout the study, participants will undergo regular health checks, including blood and urine tests, heart monitoring with an ECG (a test that records the electrical activity of the heart), and assessments of vital signs like blood pressure and body temperature. These evaluations will help researchers understand the effects of GLM101 and ensure the safety of the participants. The study is expected to continue for several years, allowing for a comprehensive assessment of the treatment’s long-term impact on individuals with PMM2-CDG.