• mitochondrial metabolic disorders (E88.4-)
  1. Q90 Down syndrome

    1. Q90.0 Trisomy 21, nonmosaicism (meiotic nondisjunction)

    2. Q90.1 Trisomy 21, mosaicism (mitotic nondisjunction)

    3. Q90.2 Trisomy 21, translocation

    4. Q90.9 Down syndrome, unspecified

      Inclusion term(s):

      • Trisomy 21 NOS
Abbreviations used here:

NEC Not elsewhere classifiable
This abbreviation in the Tabular List represents “other specified”. When a specific code is not available for a condition, the Tabular List includes an NEC entry under a code to identify the code as the “other specified” code.

NOS Not otherwise specified
This abbreviation is the equivalent of unspecified.