Patients with type III glycogen storage disease (GSDIII) can develop liver fibrosis, which can be complicated by liver failure or even hepatocellular carcinoma. Since the beginning of the 21st century, non-invasive techniques for assessing fibrosis, such as liver elastography, have been developed. These techniques often make it possible to avoid liver biopsies during patient follow-up and have already been validated in the management of several diseases in adults. These techniques are also beginning to be recommended for monitoring certain chronic liver diseases in children.

Inclusion Criteria:

• Minors: from birth to 17 years
• Adults: 18 to 21 years
• Subjects being monitored for type III glycogen storage disease and having had at least one liver elastography measurement during their follow-up.

Exclusion Criteria:

- Patients monitored for type III glycogen storage disease but who had never undergone liver elastography during their follow-up.

Patients under 22 years of age