Free Medical Coding > ICD10 CM > 2024 ICD-10-CM Codes > 2024 ICD-10-CM Codes Q00-Q99 – Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99) > 2024 ICD-10-CM Codes Q90-Q99 – Chromosomal abnormalities, not elsewhere classified (Q90-Q99) > 2024 ICD-10-CM Codes Q90 – Down syndrome (Q90)