This is an observational study of individuals with achondroplasia in the United States. The primary study population consists of pediatric individuals treated and untreated with VOXZOGO™. Study enrollment started in February 2023. The projected total duration of the study is approximately 5 years at minimum from start of study recruitment in February 2023, with the duration of individual prospective follow-up differing depending on the time of enrollment. The study duration may be extended based on decisions by the study sponsor.

Data will be collected in two formats for the primary pediatric study population:

1. Participant-mediated access to electronic health records(including medical imaging, when available) which will enable retrospective and prospective collection of secondary data reflecting real-life treatment use and clinical care. .
2. Primary data collection of Clinical Outcome Assessments (COAs) and questionnaire data.

Data will be collected in the following format for the adult cohort:

- Participant-mediated access to electronic health records (including medical imaging, when available) which will enable retrospective and prospective collection of secondary data reflecting real-life treatment use and clinical care.

The primary study population will include approximately 150 pediatric individuals with achondroplasia regardless of their treatment status with VOXZOGO™. Individuals may change status from untreated to treated during the prospective period of the study (or vice versa) however they will only be counted once, based on their treated status at the point of enrollment.

The secondary study population will include 20 adolescent and adult participants.

Inclusion Criteria:

• Physician diagnosis of achondroplasia
• Age at time of enrollment:

Primary Pediatric Cohort: ≤13 years old Secondary Adolescent and Adult Cohort: ≥14 years old

• Receiving medical care in the United States
• Complete PicnicHealth's onboarding process, including signing informed consent and authorization for medical record retrieval

Exclusion Criteria:

• Lack of any medical records

The primary study population will include individuals with achondroplasia regardless of their treatment status with VOXZOGO™. Whilst individuals may change status from untreated to treated during the prospective period of the study (or vice versa), for the purposes of recruitment targets they will only be counted once, based on their treated status at the point of enrollment