Q99 Other chromosome abnormalities, not elsewhere classified

Category / Non-billable header 12 subcodes

Block: Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
Q99..0 Chimera 46, XX/46, XY Yes
Q99..1 46, XX true hermaphrodite Yes
Q99..2 Fragile X chromosome Yes
Q99..8 Other specified chromosome abnormalities No
Q99..81 Usher syndrome No
Q99..811 Usher syndrome, type 1 Yes
Q99..812 Usher syndrome, type 2 Yes
Q99..813 Usher syndrome, type 3 Yes
Q99..818 Other Usher syndrome Yes
Q99..819 Usher syndrome, unspecified Yes
Q99..89 Other specified chromosome abnormalities Yes
Q99..9 Chromosomal abnormality, unspecified Yes

Last reviewed: September 2026