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Q90.1

Billable

Trisomy 21, mosaicism (mitotic nondisjunction)

This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

Down syndrome where some cells have three copies of chromosome 21 while others have the normal two copies, resulting from a cell division error after conception.

Coding Tips

  • •Mosaicism typically results in milder symptoms than nonmosaicism; document the percentage of affected cells if available
  • •Code any associated complications separately

Code Hierarchy

└Q90Down syndrome└Q90.1Trisomy 21, mosaicism (mitotic nondisjunction)
└Q90.1Trisomy 21, mosaicism (mitotic nondisjunction)

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