Achondroplasia is a genetic disorder characterized by disproportionate short stature. It affects about 1 in 2500 live births in the world. The cause of Achondroplasia was identified to be a gain-of-function mutations in the fibroblast growth receptor 3 (FGFR3). In these children compression of the spinal cord at the foramen magnum stenosis can occur in early childhood which, can lead to central sleep apnea. It can lead to morbidity and mortality. A surgical intervention may be indicated in patients who present a foramen magnum stenosis. However, surgical indications are still under discussion. The objective of this retrospective study is to analyse the degree of stenosis and its clinical tolerance/evolution from radiological data monitored at the Hospital Femme Mère Enfant.

Inclusion Criteria:

• Boys and girls.
• Aged from 0 to 18 years old.
• Subjects with an Achondroplasia diagnosis.
• Patients or parents/ legal guardian must provide non opposition prior to participation in the study.

Exclusion Criteria:

- Patients or patient's parents or legal guardian whose have an objection for using their data.

Patients with Achondroplasia