This clinical trial is focused on studying a rare genetic disorder called PMM2-CDG (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, including problems with movement and coordination, known as ataxia. The study is testing a new treatment called GLM101, which is given through an intravenous infusion, meaning it is administered directly into the bloodstream. The purpose of the study is to evaluate the effectiveness and safety of GLM101 in improving symptoms of PMM2-CDG, particularly focusing on changes in ataxia over a period of 24 weeks.

Participants in the study will receive weekly doses of either GLM101 or a placebo. The study is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. This helps ensure that the results are not biased. The study will last for up to 48 weeks, with participants being monitored for any changes in their condition and any potential side effects. The main goal is to see if GLM101 can improve movement and coordination in people with PMM2-CDG compared to those who receive a placebo.

Throughout the study, participants will undergo various assessments to track their progress. These assessments will include evaluations of their movement and coordination, as well as overall health checks to ensure safety. The study will also compare the effects of starting GLM101 treatment early versus later in the study. By the end of the trial, researchers hope to gather valuable information on how GLM101 can help manage symptoms of PMM2-CDG and improve the quality of life for those affected by this rare disorder.