Trisomy 18, nonmosaicism (meiotic nondisjunction)

This code represents Edwards syndrome, a severe chromosomal disorder caused by an extra copy of chromosome 18 in every cell of the body, resulting from a meiotic nondisjunction event. It is characterized by a distinct pattern of congenital anomalies affecting multiple organ systems.

Use this code for a confirmed diagnosis of Trisomy 18 (Edwards syndrome) where genetic testing indicates a nonmosaic presentation due to meiotic nondisjunction. Documentation should clearly state the diagnosis of Trisomy 18 and specify the nonmosaic nature, often confirmed by karyotype analysis.

• Differentiate from mosaic Trisomy 18, which has a separate code.
• Do not use for partial Trisomy 18; specific codes exist for those conditions.
• Sequence as the primary diagnosis when it is the reason for the encounter or hospitalization.