The main objective for this study is to evaluate the pharmacokinetics (PK) of crinecerfont in pediatric participants 0 to <2 years of age with congenital adrenal hyperplasia (CAH).

Key Inclusion Criteria:

• Be a female or male between 0 to <2 years of age at screening.
• Have a medically confirmed diagnosis of classic CAH (salt wasting or simple virilizing) due to 21-hydroxylase deficiency (21-OHD).
• Be on a clinically stable regimen of hydrocortisone (and fludrocortisone, if applicable) treatment.

Key Exclusion Criteria:

• Have a known or suspected diagnosis of any of the other forms of classic CAH.
• Have any condition besides CAH that requires chronic daily therapy with orally administered steroids.
• Have any other clinically significant medical condition or chronic disease.

Note: Other protocol-defined inclusion and exclusion criteria may apply.