Chromosomal abnormalities, not elsewhere classified
88 codes in this section
About Section Q90-Q99
Section Q90-Q99 (Q90-Q99) covers chromosomal abnormalities, not elsewhere classified. It sits within the Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders chapter (Q00-QA0). This section contains 88 ICD-10-CM codes, 74 billable diagnoses you can submit on a claim, and 14 non-billable header codes used to organize the hierarchy.
Codes are organized below by 3-character root. Click the root to see all subcodes underneath it, or click any individual code for full coverage data, payer policies, and linked CPT procedures.
Codes in Q90-Q99
Grouped by 3-character root code. Click any code for full detail.
| Q90.0 | Trisomy 21, nonmosaicism (meiotic nondisjunction) | Billable |
| Q90.1 | Trisomy 21, mosaicism (mitotic nondisjunction) | Billable |
| Q90.2 | Trisomy 21, translocation | Billable |
| Q90.9 | Down syndrome, unspecified | Billable |
| Q91.0 | Trisomy 18, nonmosaicism (meiotic nondisjunction) | Billable |
| Q91.1 | Trisomy 18, mosaicism (mitotic nondisjunction) | Billable |
| Q91.2 | Trisomy 18, translocation | Billable |
| Q91.3 | Trisomy 18, unspecified | Billable |
| Q91.4 | Trisomy 13, nonmosaicism (meiotic nondisjunction) | Billable |
| Q91.5 | Trisomy 13, mosaicism (mitotic nondisjunction) | Billable |
| Q91.6 | Trisomy 13, translocation | Billable |
| Q91.7 | Trisomy 13, unspecified | Billable |
| Q92.0 | Whole chromosome trisomy, nonmosaicism (meiotic nondisjunction) | Billable |
| Q92.1 | Whole chromosome trisomy, mosaicism (mitotic nondisjunction) | Billable |
| Q92.2 | Partial trisomy | Billable |
| Q92.5 | Duplications with other complex rearrangements | Billable |
| Q92.6 | Marker chromosomes | Header |
| Q92.61 | Marker chromosomes in normal individual | Billable |
| Q92.62 | Marker chromosomes in abnormal individual | Billable |
| Q92.7 | Triploidy and polyploidy | Billable |
| Q92.8 | Other specified trisomies and partial trisomies of autosomes | Billable |
| Q92.9 | Trisomy and partial trisomy of autosomes, unspecified | Billable |
| Q93.0 | Whole chromosome monosomy, nonmosaicism (meiotic nondisjunction) | Billable |
| Q93.1 | Whole chromosome monosomy, mosaicism (mitotic nondisjunction) | Billable |
| Q93.2 | Chromosome replaced with ring, dicentric or isochromosome | Billable |
| Q93.3 | Deletion of short arm of chromosome 4 | Billable |
| Q93.4 | Deletion of short arm of chromosome 5 | Billable |
| Q93.5 | Other deletions of part of a chromosome | Header |
| Q93.51 | Angelman syndrome | Billable |
| Q93.52 | Phelan-McDermid syndrome | Billable |
| Q93.59 | Other deletions of part of a chromosome | Billable |
| Q93.7 | Deletions with other complex rearrangements | Billable |
| Q93.8 | Other deletions from the autosomes | Header |
| Q93.81 | Velo-cardio-facial syndrome | Billable |
| Q93.82 | Williams syndrome | Billable |
| Q93.88 | Other microdeletions | Billable |
| Q93.89 | Other deletions from the autosomes | Billable |
| Q93.9 | Deletion from autosomes, unspecified | Billable |
| Q95.0 | Balanced translocation and insertion in normal individual | Billable |
| Q95.1 | Chromosome inversion in normal individual | Billable |
| Q95.2 | Balanced autosomal rearrangement in abnormal individual | Billable |
| Q95.3 | Balanced sex/autosomal rearrangement in abnormal individual | Billable |
| Q95.5 | Individual with autosomal fragile site | Billable |
| Q95.8 | Other balanced rearrangements and structural markers | Billable |
| Q95.9 | Balanced rearrangement and structural marker, unspecified | Billable |
| Q96.0 | Karyotype 45, X | Billable |
| Q96.1 | Karyotype 46, X iso (Xq) | Billable |
| Q96.2 | Karyotype 46, X with abnormal sex chromosome, except iso (Xq) | Billable |
| Q96.3 | Mosaicism, 45, X/46, XX or XY | Billable |
| Q96.4 | Mosaicism, 45, X/other cell line(s) with abnormal sex chromosome | Billable |
| Q96.8 | Other variants of Turner's syndrome | Billable |
| Q96.9 | Turner's syndrome, unspecified | Billable |
| Q97.0 | Karyotype 47, XXX | Billable |
| Q97.1 | Female with more than three X chromosomes | Billable |
| Q97.2 | Mosaicism, lines with various numbers of X chromosomes | Billable |
| Q97.3 | Female with 46, XY karyotype | Billable |
| Q97.8 | Other specified sex chromosome abnormalities, female phenotype | Billable |
| Q97.9 | Sex chromosome abnormality, female phenotype, unspecified | Billable |
| Q98.0 | Klinefelter syndrome karyotype 47, XXY | Billable |
| Q98.1 | Klinefelter syndrome, male with more than two X chromosomes | Billable |
| Q98.3 | Other male with 46, XX karyotype | Billable |
| Q98.4 | Klinefelter syndrome, unspecified | Billable |
| Q98.5 | Karyotype 47, XYY | Billable |
| Q98.6 | Male with structurally abnormal sex chromosome | Billable |
| Q98.7 | Male with sex chromosome mosaicism | Billable |
| Q98.8 | Other specified sex chromosome abnormalities, male phenotype | Billable |
| Q98.9 | Sex chromosome abnormality, male phenotype, unspecified | Billable |
| Q99.0 | Chimera 46, XX/46, XY | Billable |
| Q99.1 | 46, XX true hermaphrodite | Billable |
| Q99.2 | Fragile X chromosome | Billable |
| Q99.8 | Other specified chromosome abnormalities | Header |
| Q99.81 | Usher syndrome | Header |
| Q99.811 | Usher syndrome, type 1 | Billable |
| Q99.812 | Usher syndrome, type 2 | Billable |
| Q99.813 | Usher syndrome, type 3 | Billable |
| Q99.818 | Other Usher syndrome | Billable |
| Q99.819 | Usher syndrome, unspecified | Billable |
| Q99.89 | Other specified chromosome abnormalities | Billable |
| Q99.9 | Chromosomal abnormality, unspecified | Billable |
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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