Potential gene therapy for LGMD shows early signs of helping muscle health

16 October 2025

In limb-girdle muscular dystrophy R4 (LGMDR4), a change in the SGCB gene affects a protein called beta-sarcoglycan. This protein helps keep muscles healthy. A potential gene therapy called SRP-9003 is being tested to add a working copy of the SGCB gene back into the body. It’s particularly designed to help the heart muscle, which can be seriously affected in LGMDR4.

The working gene is delivered using a virus called an AAV vector. In the trial, 17 people with LGMD were treated with SRP-9003. After 60 days, researchers checked levels of beta-sarcoglycan protein. In people who were able to walk, levels increased by 43%. This suggests the treatment is doing what it’s meant to do – helping the body make more of the missing protein.

Safety is very important in any clinical trial. Other treatments using AAV vectors, like Elevidys for Duchenne muscular dystrophy (DMD), have been linked to serious side effects, including liver damage, and in a small number of cases, death. In this trial, more than 40% of participants showed signs of liver injury. However, the company running the trial (Sarepta) says these events were not caused by SRP-9003.

Sadly, three deaths have recently been linked to the AAV vector used in these types of treatments. Because of this, the SRP-9003 trial is currently paused while safety checks are carried out.