Prospective Clinical Assessment Study in Children With Achondroplasia (ACH)

Key Inclusion Criteria: * Signed informed consent by study participant or parent(s) or legally authorized representative (LAR) and signed informed assent by the study participant (when applicable) * Aged 2.5 to \<17 years at study entry * Diagnosis of ACH * Study participants and parent(s) or LAR(s) are willing and able to comply with study visits and study procedures Key Exclusion Criteria: * Have hypochondroplasia or short stature condition other than ACH (e.g. trisomy 21, pseudoachondroplasia, psychosocial short stature) * In females, having had their menarche * Height \< -2 or \> +2 standard deviations for age and sex based on reference tables on growth in children with ACH * Annualized height growth velocity ≤1.5 cm/year over a period ≥6 months prior to screening * Current evidence of corneal or retinal disorder/keratopathy * Current evidence of endocrine alterations of calcium/phosphorus homeostasis * Have a concurrent disease or condition that in the view of the Investigator and/or Sponsor, may impact growth or where the treatment is known to impact growth. * Significant abnormality in screening laboratory results. * Have been treated with growth hormone, insulin-like growth factor 1 (IGF 1), or anabolic steroids in the previous 6 months or long-term treatment (\>3 months) at any time * Have had regular long-term treatment (\>1 month) with oral corticosteroids (low-dose ongoing inhaled steroid for asthma is acceptable) * Have had previous guided growth surgery or limb-lengthening surgery within 12 months prior to screening.